Manual for doctors

GOU DPO "Irkutsk State Institute of Advanced Training"

7. Reagent strips for protein determination. 47

8. Reagent strips for determination of nitrites. 47

10. Reagent strips for the determination of ascorbic acid. 48

Methods for assessing urine sediment.. 49

Quality control of urine analysis... 53

Intralaboratory control (ILC) 53

Rules for intra-laboratory quality control of quantitative laboratory studies. 53

1. Basic provisions. 54

1.1. Terms and definitions used in the document. 54

1.2. Measurement errors. 54

2. In-laboratory quality control of laboratory research using control materials. 56

2.1. Control materials: types, requirements, recommendations for selection, rules of use. 56

2.1.1. Types of control materials. 56

2.1.3. Use of control materials. 58

External quality assessment... 59

Determination of protein in urine in the external quality assessment system... 62

Questions for self-monitoring on clinical laboratory diagnostics of urine... 63

Answers to questions... 77

References... 79

“The doctor must observe whether the urine of a patient is the same as that of a healthy person, and the less similarity, the more severe the disease” (Hippocrates, (460-377 BC)

Introduction

A manual for doctors of any specialties can be a collected material presenting urine analysis as a process reflecting changes in the physicochemical properties of urine in conjunction with pathophysiological abnormalities at the time of a particular etiological condition. It is important to have a clear understanding of the process under study from the standpoint of the anatomical structure of human organs in which changes occur that affect the area of ​​the analyzed material. For an objective assessment of the analysis, its correctness and accuracy, it is important to know not only classical methods for determining certain parameters of urine analysis, but also modern methods that make it possible to more reliably judge the ongoing disease on the basis of clinical laboratory analysis. Since standardization in any comparison is the basis for the correctness of the analysis, it is necessary to pay some attention to the documents regulating the quality control of urine analysis studies.

Considering all of the above, we have tried to combine in this manual information of a fundamental nature, applied materials on the use of the main indicators of general clinical urine analysis, highlight classical and modern methods of urine analysis, and also discuss quality criteria based on in-laboratory and external controls.

Human urinary system

The human urinary system is anatomically represented by the kidneys, ureters, bladder and urethra. The kidneys are the most important organ of the urinary system (Fig. 1). The importance of the kidneys for the body is not limited to their excretory function. The kidneys are involved in the metabolism of proteins and carbohydrates, participate in the production of erythropoietins, and, therefore, participate in the process of erythropoiesis, produce renin and prostaglandins, which determines the hormonal function of the kidneys. In addition, the kidneys play a great role in regulating blood pressure and maintaining the constancy of the body’s liquid internal environment (pH, osmotic pressure), as well as in regulating the metabolism of various organic and inorganic substances.

The listed functions of the kidney are based on the processes occurring in its parenchyma: ultrafiltration in the glomeruli, reabsorption and secretion of substances. In the normal physiological state of a person, from 1/4 to 1/5 of the total blood volume passes through the kidneys, which make up only about 0.43% of body weight. In the kidneys there is a system of cortical and cerebral blood flow. Although their vascular capacity is approximately the same, about 94% of the blood flows through the cortical vascular system and only 6% through the cerebral vascular system. The highest level of organ blood flow is recorded in the renal cortex and reaches 4-5 ml/min per 1 gram of tissue.

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Rice. 1. Kidney structure.

Cortical blood flow is closely connected with the capillaries of the glomerulus. One of the main features that distinguishes cortical blood flow from cerebral blood flow is that within a wide range of changes in blood pressure (from 90 to 190 mm Hg), the cortical blood flow of the kidney remains almost constant. This is due to a special system of self-regulation of cortical blood flow. Self-regulation of cortical blood flow ensures the constancy of the processes underlying urine formation in conditions of significant changes in extrarenal hemodynamics.

The main structural and functional unit of the kidney is the nephron. Each human kidney contains about 1 million nephrons. Each nephron includes a glomerulus with a capsule, a convoluted tubule of the first order, a loop of Henle, a convoluted tubule of the second order and a collecting duct (Fig. 2.).

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Rice. 2. Structure of the nephron: 1. afferent arteriole; 2. efferent arteriole; 3. glomerulus of capillaries; 4. Shumlyansky capsule; 5. capsule cavity; 6. proximal convoluted tubule; 7. descending limb of the loop of Henle; 8. ascending limb of the loop of Henle; 9. distal convoluted

tubule; 10. collecting duct.

The initial stage of urine formation occurs in the glomeruli - filtration of protein-free liquid - primary urine - from the blood plasma into the capsule of the renal glomerulus. The second stage is due to the fact that this liquid moves through the tubules, where water and substances dissolved in it are reabsorbed at different rates. The third process - tubular secretion - consists of nephron epithelial cells taking up a certain amount of substance from the blood and intercellular fluid and transferring them into the lumen of the tubule. The most important feature of the kidney is that the efferent vessel of the glomerulus is an arterial type vessel, not a venous one. In all other organs, diverting blood from the capillaries, the vessels have venous walls and a larger diameter than the afferent artery.

In just one day, up to 2000 liters of blood flows through the kidneys. Urine is formed in the kidneys and consists of solutions of organic and inorganic substances. The kidneys themselves do not produce new substances, but only secrete substances already contained in the blood. Moreover, blood homeostasis (constancy of blood composition) is ensured mainly due to the excretory function of the kidneys. With various diseases, all sorts of pathological metabolic products enter the blood, which, when excreted in the urine, can help in diagnosing the pathological process.

On average, a healthy person excretes ml of urine per day, depending on fluid intake, sweating, and external temperature. Normally, the ratio of daytime to nighttime diuresis is 3:1 or 4:1, and the frequency of urination is 3-4 times a day.

General urine analysis as a mandatory test for diagnosing diseases

A general urine test is included in the list of mandatory tests that should be performed on all patients who initially apply, regardless of the expected diagnosis. In a general clinical analysis of urine, its physical properties (color, transparency, smell, reaction, relative density), the content of certain substances (protein, glucose, hemoglobin, bile pigments, ketone bodies, urobilin) ​​are assessed, and a microscopic examination of the sediment is also carried out. In this case, leukocytes, erythrocytes, epithelial cells from various parts of the urinary system, various cylinders, salt crystals, bacteria and other ingredients can be detected. Changes in the properties of urine and an increased content of various substances and elements allow the doctor to identify some pathological processes (in particular in the kidneys), and in combination with general clinical and biochemical blood tests, to more accurately diagnose the disease (including those related to other organs and systems).

Sample collection and preparation for general urine analysis

The result of a urine test largely depends on how the object for analysis is collected and delivered to the laboratory. For a routine analysis, it is enough to collect the first morning portion of urine in a colorless glass container with a flat bottom. These dishes must first be thoroughly washed. Before collecting urine, it is necessary to carefully wash the external genitalia (especially for women). For women during menstruation, urine is usually not examined, but, if necessary, is collected with a catheter. If for some reason the study cannot be carried out soon after collecting urine, then it is better to store it in a cold place. For bacteriological examination, the external genitalia are washed with a disinfectant solution and the urine is collected in a sterile container, which is immediately covered with a sterile lid. You can store urine for no more than 1.5 hours before conducting a general analysis. A later urine test will be unreliable because its cellular composition changes.

Normal values ​​of general clinical urine examination indicators

Table 1 presents all the main indicators taken into account during a general clinical examination of urine and their normal values. These indicators do not depend on gender and age.

Table 1

Main indicators of general clinical urine analysis

Index
Physical properties
Quantity	ml per day
	straw yellow
Transparency	transparent
	not sharp, not specific
Relative density
Chemical properties
	slightly sour
	absent
	absent
Ketone bodies	absent
Bilirubin	absent
Urobilinoids	absent
Bile acids	absent
Microscopic examination of sediment
Epithelium	Single cells
Leukocytes	0-4 in sight
Red blood cells	single in a smear
Cylinders
	no or insignificant quantity
Bacteria	less than 106 in 1 ml

Study of the physical properties of urine

1. Amount of urine

Diuresis is the volume of urine produced over a certain period of time (daily or minute diuresis). Up to 1.5 liters of urine are excreted from the human body per day. Urine is 95% water; 5% comes from solids. Its main components are the end products of nitrogen metabolism: urea (2%), uric acid (0.5%), creatinine (0.075%). The rest comes mainly from salts. An average of 30 g of urea and 25-30 g of its organic salts are excreted in the urine per day. The specific gravity of urine is 1020. The active reaction can be acidic, neutral or alkaline. The amount of urine delivered for general analysis (usually 150–200 ml). The patient must record daily diuresis independently and report it when submitting urine for a general analysis.

Interpretation of the analysis

Oliguria is a marked decrease in the daily amount of urine. Daily volume 50-400 ml. (febrile conditions, heart disease, acute renal failure, nephrosclerosis)‏;

Anuria is a complete cessation of urine flow into the bladder. Daily volume 0-50 ml (acute renal failure, severe nephritis, meningitis, poisoning, peritonitis, blockage of the urinary tract by a tumor or stone);

Ischuria is urinary retention in the bladder due to the inability to urinate independently (adenoma and prostate cancer, prostatitis, urethral stricture, blockage of the urinary canal with a stone or tumor, disruption of the neuromuscular apparatus of the bladder;

Polyuria – an increase in the daily amount of urine (resorption of edema, transudates, exudates, diabetes mellitus and diabetes insipidus)‏;

Nocturia – increased nocturnal diuresis (at the initial stage of cardiac decompensation, with cystitis, cystopyelitis);

Polakiuria is frequent urination. Polakiuria is not always combined with polyuria (inflammation of the urinary tract, colds, prostatitis, in nervous children);

Olakiuria is rare urination. (for neuro-reflex disorders). (Olakiuria is not always accompanied by oliguria);

2. Urine color

Normally, urine is yellow in color (from straw to amber yellow). The saturation of the yellow color of urine depends on the concentration of substances dissolved in it. With polyuria, the dilution is greater, so the urine has a lighter color; with a decrease in diuresis, the urine acquires a rich yellow tint. The color of urine is determined by the content of pigments in it: urochromes A and B, uroerethrin, urobilin, hematoporphyrin, urozein and other substances formed from blood pigments.

The color of urine may change due to the consumption of certain foods, the use of certain medications, and certain pathological conditions.

Interpretation of the analysis

The color of meat slops indicates gross hematuria (altered blood), for example, in acute nephritis;

Red color indicates gross hematuria (whole blood), for example, in renal colic, renal infarction;

The color of the beer indicates the excretion of bile pigments in the urine in parenchymal or obstructive jaundice;

A greenish-yellow color is characteristic when there is a large amount of pus in the urine;

A pale, watery color is observed with a low concentration of dyes, for example, with diabetes mellitus and diabetes insipidus;

Dark, almost black color of urine indicates hemoglobinuria in acute hemolytic anemia. The same color is given by melanin in myeloma or myelosarcoma;

Whitish color of urine is characteristic of a large amount of phosphates in the urine or lipuria, when fat is excreted in the urine.

A pronounced increase in color intensity occurs due to an increase in the concentration of coloring substances in the urine, for example:

For heart failure;

With increasing swelling;

With loss of fluid due to vomiting, diarrhea, burns.

In addition to the color of urine, visualization of the color of urine sediment is also used as a diagnosis:

Brick red or pink color indicates high urate content;

Urine sediment in the form of yellow sand is observed with a high content of uric acid;

The dense white sediment of urine determines a large amount of tripelphosphates and amorphous phosphates;

Creamy, green-tinged urine sediment is characteristic of a large amount of pus;

Reddish or brown urine sediment indicates the presence of blood in the urine;

A gelatinous urine sediment is noted in the presence of mucus.

3. Transparency of urine

Normally, freshly released urine is completely clear. Turbidity of urine is due to the presence in it of a large number of cellular formations, salts, mucus, bacteria, and fat. Information about the turbidity of a urine sample can be obtained in 3 options: “Transparent” (“Clear”), “Opaque” (“Unclear”) and “Curdy” (“Very Unclear”).

Methods for determining the composition of components that cause turbidity in urine:

Turbidity caused by urates disappears when the urine is heated or when 10% alkali is added;

Turbidity due to phosphates is reduced by adding 30% acetic or hydrochloric acid;

Turbidity due to oxalates disappears only when hydrochloric acid is added;

The turbidity associated with the presence of fat disappears when ether is added;

Turbidity associated with the presence of pus does not disappear either with the addition of alkalis or acids, or with heating.

Interpretation of the analysis

Cloudy urine may indicate microhematuria, but in most cases it is a sign of infection (ie, bacteriuria). Visual analysis of urine can be used as a preliminary test for the presence of a urinary tract infection in asymptomatic patients. The sensitivity of visual examination of urine samples for diagnosing bacteriuria is 73%.

4. Urine smell

Normally, the smell of urine is mild and nonspecific.

Interpretation of the analysis

An ammonia odor occurs when urine is decomposed by bacteria in the air or inside the bladder, for example in the case of cystitis.

Rotted urine that contains protein, blood, or pus, such as bladder cancer, causes the urine to smell like rotten meat. If there are ketone bodies in the urine, the urine has a fruity odor, reminiscent of the smell of rotting apples.

5. Specific gravity of urine (relative density of urine)

To determine the specific gravity of urine using a urometer, at least 100 ml of urine is required. When determining specific gravity using test strips, you can get by with a smaller amount of urine, but not less than 15 ml.

Normally, the morning portion has a specific gravity in the range of 1.018-1.024 g/l.

Relative density of urine (the density of urine is compared with the density of water) reflects the functional ability of the kidneys to concentrate and dilute and can be used as a screening test during mass examinations of the population.

Figures of relative density of morning urine equal to or exceeding 1.018 g/l indicate normal concentrating ability of the kidneys and eliminate the need to study it using special methods. High or low figures for the specific gravity (density) of morning urine necessarily require clarification of the reasons behind these changes.

Interpretation of the analysis

High specific gravity of urine

The relative density of urine depends on the molecular weight of the particles dissolved in it. Protein and glucose increase the specific gravity of urine. For example, diabetes mellitus can be suspected only by one general urine test with relative density figures of 1.030 g/l and higher against the background of polyuria.

Low specific gravity of urine

The process of urine formation is regulated by the concentrating mechanism of the kidneys and the antidiuretic hormone (ADH) produced by the pituitary gland. In the presence of antidiuretic hormone, more water is absorbed, resulting in a small amount of concentrated urine. Accordingly, in the absence of antidiuretic hormone, water absorption does not occur and large volumes of diluted urine are released.

There are three main groups of reasons for the decrease in specific gravity in the general urine analysis - excess water consumption, neurogenic diabetes insipidus, nephrogenic diabetes insipidus

Excessive water consumption (polydipsia) causes a decrease in the concentration of salts in the blood plasma. To protect itself, the body secretes large volumes of diluted urine. There is a disease called involuntary polydipsia, which, as a rule, affects women with unstable mental health. The leading signs of involuntary polydipsia are polyuria and polydipsia, low relative density in a general urine test.

Neurogenic diabetes insipidus is insufficient secretion of an adequate amount of antidiuretic hormone. The mechanism of the disease is the inability of the kidneys to retain water through concentrated urine. If the patient is deprived of water, diuresis almost does not decrease and dehydration develops. The relative density of urine may decrease below 1.005 g/l.

The main causes of neurogenic diabetes insipidus:

Hypopituitarism is a failure of the pituitary gland or hypothalamus with a decrease or cessation of production of tropic hormones of the anterior pituitary gland and antidiuretic hormone. The most common cause of decreased urine specific gravity is idiopathic neurogenic diabetes insipidus. Idiopathic neurogenic diabetes insipidus is most often found in young adults. Most of the underlying disorders leading to neurogenic diabetes insipidus can be identified by associated neurological or endocrinological symptoms (including cephalalgia and visual field impairment or hypopituitarism).

Another common cause of decreased specific gravity of urine is damage to the hypothalamic-pituitary region due to head trauma, neurosurgical intervention in the pituitary gland or hypothalamus. Or damage as a result of a brain tumor, thrombosis, leukemia, amyloidosis, sarcoidosis, encephalitis after an acute infection, etc.

Taking ethyl alcohol is accompanied by reversible suppression of ADH secretion and short-term polyuria. Diuresis occurs 30-60 minutes after taking 25 g of alcohol. The volume of urine depends on the amount of alcohol taken in a single dose. Continuous use does not lead to sustained urination, despite the existence of a constant concentration of alcohol in the blood.

Nephrogenic diabetes insipidus is a decrease in the concentrating ability of the kidneys, despite the normal content of antidiuretic hormone in the blood.

The main causes of nephrogenic diabetes insipidus:

The most numerous subgroup among patients with nephrogenic diabetes insipidus consists of persons with parenchymal kidney diseases (pyelonephritis, various types of nephropathies, tubulointerstitial nephritis, glomerulonephritis) and chronic renal failure.

Metabolic disorders:

Conn's syndrome is a combination of polyuria with arterial hypertension, muscle weakness and hypokalemia. The relative density of urine can range from 1003 to 1012).

Hyperparathyroidism - polyuria, muscle weakness, hypercalcemia and nephrocalcinosis, osteoporosis. The relative density of urine decreases to 1002. Due to the significant content of calcium salts, urine is often white.

Rare cases of congenital nephrogenic diabetes insipidus. The relative gravity of urine may drop below 1.005.

Chemical examination of urine

1. Urine reaction

Normally, the urine reaction is acidic.

Fluctuations in urine pH are determined by the composition of the diet: a meat diet determines the acidic reaction of urine, while a vegetable diet determines the alkaline reaction. With a mixed diet, mainly acidic metabolic products are formed, so it is believed that the urine reaction is normally acidic.

Before carrying out a general analysis, urine should be stored in a cold room and for no more than 1.5 hours. When standing in a warm room for a long time, urine decomposes, ammonia is released and the pH shifts to the alkaline side. The alkaline reaction underestimates the relative density of urine. In addition, white blood cells are quickly destroyed in alkaline urine. The reaction of urine, as well as the relative density, should be taken into account during subsequent microscopy of the sediment. When urine is alkaline and has a low relative density, cells are quickly destroyed. Immediate microscopy is necessary.

Interpretation of the analysis

Acid reaction (<5.5) наблюдается обычно в следующих случаях:

Under physiological conditions, when the diet is overloaded with meat foods;

In case of pathology - in case of acidosis, acute nephritis, gout, diabetes, starvation, severe diarrhea.

An alkaline urine reaction (>6.0) is characteristic of chronic urinary tract infection, and is also observed with diarrhea and vomiting.

The acidity of urine increases in feverish conditions, diabetes mellitus, tuberculosis of the kidneys or bladder, and renal failure.

2. Protein in urine

Normally, there is no protein in the urine. Although in fact there is a physiological release of protein from the urinary tract and prostate gland (in men), it does not exceed 150 mg/day. Such a small concentration is not detected in single portions. Therefore, normally there is no protein in a general urine test.

The excretion of protein in the urine is called proteinuria. Previously, the term albuminuria was used, but then it turned out that not only albumin is secreted. The concentration of protein in a single portion of urine, expressed in grams per 1 liter, does not give an idea of ​​​​the absolute amount of protein lost, so protein losses must be looked at in daily urine (normally no more than 150 mg/day.) There are three degrees of proteinuria: Moderate - up to 1 g of protein per day; Average – 1-3 g; Expressed – more than 3 g.

Protein is determined using one of the quantitative methods, as a result of which the protein concentration in g/l is determined. (Methods for the quantitative determination of protein will be described below, since this issue remains relevant for various laboratories in Russia). To determine daily proteinuria, you need to recalculate, taking into account the daily amount of urine.

Formula for calculating daily proteinuria

A = n * v mg/day,

where n is the amount of protein in mg/l, v is the volume of daily urine in ml.

The normal daily proteinuria rate is 150 mg/day.

Interpretation of the analysis

There are functional proteinuria and organic proteinuria.

Functional proteinuria

Functional proteinuria is not constant and occurs either when the permeability of the kidney filter membranes increases, or when blood flow in the glomeruli slows down in response to strong external stimuli (stress, fever, exercise). Hence the names of functional intermittent proteinuria - marching, emotional, cold, palpation, orthostatic.

Proteinuria should not be considered as a pathological phenomenon after various vegetative crises, colic, myocardial infarction, epilepsy, stroke or mental agitation of persons with an unstable autonomic nervous system. When eating a large amount of protein (for example, egg), nutritional proteinuria may occur, which also cannot be classified as a pathological phenomenon.

What is urine? Urine is a human waste product that is continuously formed in the kidneys and moves through the ureters to the bladder. Then, as the bladder fills, the liquid is discharged through the urethra.

Why submit your urine for analysis?

Normally, an adult produces about 1-1.8 liters of urine per day. It is a complex biological fluid, which, in addition to water, includes various organic and inorganic compounds (mineral salts, small amounts of amino acids, urea, various trace elements, inactivated hormones, enzymes, etc.).

Urine is the most adequate biological material that is used in the study of renal pathologies, prostate, organs of the urinary system, as well as diseases of other tissues and organs of the human body. That is why in laboratory diagnostics it is used as a marker that allows one to obtain important diagnostic information.

Analysis of urine– as an indicator of the overall clinical picture and deciphering the processes occurring in the body. In order for the doctor to get an idea of ​​what processes occur in the human body and find out whether they deviate from the norm, there are many methods for examining urine in laboratory practice. Based on urine analysis, a diagnosis is established, the severity of the patient’s condition is assessed, management tactics are adjusted, and drug and replacement therapy is prescribed.

Rules for collecting urine for analysis

All urine tests that are prescribed to patients are divided into two groups: routine and special, that is, those that are performed only for medical indications. In order for a urine test to adequately reflect the true picture of what is happening, as well as help identify possible health problems, it must be collected correctly.

Immediately before taking a urine test, it is not recommended to take diuretic and non-drug medications, large amounts of liquid, products that can change the color of urine, as well as some drugs that affect the qualitative composition of the biological fluid being tested.

1. As a rule, it is recommended to submit a urine test to urine collected immediately after a night's sleep, or a portion taken from thoroughly mixed daily urine.
2. In the absence of special recommendations, it should be collected in a container or small, clean and sterilized jar.
3. Before submitting urine for analysis, you need to thoroughly clean the external genitalia.
4. The first portion is flushed down the toilet, and then the remaining urine is collected in a prepared container.
5. The sample must be delivered to the laboratory no later than 2 hours after the urine is collected.

Urine collected in the evening is not suitable for urine analysis, since over time bacteria begin to multiply in it, existing salts precipitate, and other processes occur that make the result of the analysis not informative.

Types of urine tests

General urine analysis

Clinical (general) urine analysis is a routine, most common type of examination of biological fluid that does not require special preparation. This analysis involves performing a macroscopic and microscopic examination of a portion of morning urine. When analyzing urine, the laboratory technician determines the quantity, transparency, color, reaction and relative density, and also identifies the possible presence of protein and glucose.

If necessary, the presence of ketone bodies and other compounds is determined. Microscopy of sediment includes the study and counting of elements of organic and inorganic origin (leukocytes, erythrocytes, epithelial cells, salts and casts).

Urinalysis according to Nechiporenko

Urinalysis according to Nechiporenko is a technique that reveals a hidden inflammatory process in the urinary system. It is based on counting formed elements per unit volume of urine. This is a relatively simple and fairly informative urine test that does not require special preparation, which is used in the diagnosis of cystitis, pyelonephritis, hematuria and cylindruria.

For the study, an average portion of morning urine (50-100 ml) is taken.

Urinalysis according to Zemnitsky

Urinalysis according to Zemnitsky - this technique allows you to determine the excretory and concentration ability of the kidneys. To conduct a urine test, 8 portions of urine are required, which are collected every 3 hours throughout the day (collection begins at 6 a.m.). During the study, the laboratory technician determines the amount and specific gravity of urine in each portion.

Normally, daily diuresis should be about 2 liters, and the nighttime volume should be lower than the daytime volume. The reference value for specific gravity of urine is in the range of 1010-1025. Violations of volume and relative density indicators indicate the presence of pathologies such as renal failure, glomerulonephritis, pyelonephritis, diabetes mellitus, and uric acid diathesis.

Urine glucose test

Analysis of glucose content in urine - this study is carried out in a single or daily portion of urine. This is an accessible and informative technique used in diagnosing pathologies associated with impaired carbohydrate metabolism (for diseases of the adrenal glands, pancreas and thyroid glands, as well as for clinical signs of diabetes mellitus and assessing the effectiveness of its treatment).

For analysis, an average portion of a single or 100 ml of daily urine is taken. The day before the start of the collection, you should exclude food and physical activity and alcohol consumption. Normally, there is no glucose in the urine.

Determination of total protein in urine

Determination of total protein in urine. In laboratory diagnostics, this study is used to assess the functional state of the kidneys. Impaired protein absorption occurring in the proximal tubules of the kidneys signals the presence of acute and chronic infections, immune pathologies, intoxication with drugs and toxic substances, systemic or renal diseases.

The analysis requires 100 ml of daily urine. Normally, there is no protein in the urine.

Determination of creatinine in urine (sample P

Determination of creatinine in urine (Rehberg test). Creatinine is a breakdown product of phosphocreatine. It is a source of energy for the functioning of the heart muscle and skeletal muscles. It is not reabsorbed in the renal tubules and is excreted from the body along with urine. With kidney damage, the level of creatinine in the urine decreases. This study is prescribed for the diagnosis of cardiovascular pathologies, acute and chronic disorders of the kidneys, as well as endocrine diseases.

To conduct a urine test, 100 ml of daily urine is taken. At the same time, blood is donated on an empty stomach for creatinine. Normal values ​​range from 5.3-17.7 mmol/l.

Determination of uric acid

Determination of uric acid. Uric acid, synthesized as sodium salts in the liver, is excreted in the urine, ridding the body of excess nitrogen compounds. In the case when functional failures in the functioning of the kidneys occur, the metabolism of uric acid is disrupted, and it begins to accumulate in the blood, crystallizing in the joint cavities, as well as other organs and tissues (gout).

This study is carried out to determine the cause of stone formation, diagnose gout and Konovalov-Wilson disease. For analysis, 100 ml of daily urine is taken. The norm is 1.48-4.43 mmol/day.

• Urea is the final nitrogen-containing product of protein metabolism. This compound is synthesized in the liver and excreted in the urine. With a high concentration of urea in the blood and a decrease in its levels in the urine, the development of renal failure is suspected. The analysis requires 100 ml of daily urine. Reference values ​​are 333.0-587.7 mmol/day.
• Alpha amylase is a digestive enzyme produced by the pancreatic and salivary glands. Diastase, released from the body along with urine, is a marker of the condition of the pancreas. An increase in its concentration in the urine indicates an increased level in the blood. This study is prescribed to patients when diagnosing acute pancreatitis and mumps. The norm is 16-64 EU.

Urine hCG test to determine pregnancy

Human chorionic gonadotropin begins to be released by the chorion (germinal tissues) on the fourth day after fertilization. An increase in the concentration of hCG in the blood of a pregnant woman occurs 7-10 days from the moment of conception. It is then that it enters unchanged into the urine, where it is detected using qualitative analysis.

Morning urine is taken for research, since it contains the largest amount of the hormone human chorionic gonadotropin.

Bacteriological culture of urine for flora and sensitivity to antibiotics and bacteriophages

When analyzing urine, the test identifies bacteria present in the urine and also determines their concentration. To do this, the biological fluid taken from the catheter is placed in a nutrient medium and the growth of microorganisms is observed. If there is none, the result is considered negative, and if strains of the causative agent of a particular infection are identified, it is considered positive.

If an infectious agent is detected in urine during analysis, bacteriological studies are carried out, and based on the results of assessing sensitivity to antibiotics and bacteriophages, etiotropic therapy is prescribed. In this case, reference values ​​for each type of microorganism are taken into account.

Of course, many of us have given up at some point in our lives. After all, even a child knows that the results of the study help to identify certain diseases or control their condition. Therefore, urine is an important “tool” for the clinical diagnosis of human health.

However, the information obtained from the analysis may depend on the method of collection of the material. We will consider what types and their characteristics exist in this article. In addition, we will find out how to properly collect and transport material for research.

Why is this being done?

First of all, let's determine why you need to submit your urine to a laboratory for analysis:

• To check for urinary tract diseases or infections. Symptoms can be very different: bad smell of urine, pain when urinating, blood, pain in the side and others.
• To monitor the condition of various diseases, such as diabetes, kidney stones, urinary tract infections, high blood pressure, or certain kidney and liver diseases.
• For a regular physical examination, a urine test is also performed, the types of which are determined by the doctor.

How to prepare?

• Before submitting your urine for analysis, you should not eat foods that can color it. Namely: blackberries, beets, rhubarb and others.
• Do not do strenuous training before the test.
• It is important for women to tell their doctor about their menstrual cycles. If necessary, the specialist will postpone the urine test for several days. The types and methods of conducting such research are assigned individually.
• Your doctor may also ask you not to take medications that affect the color of your urine (usually B vitamins, Rifampicin, and Phenytoin) for a while.
• If you are taking diuretics, be sure to tell your doctor. Because they can significantly influence research results.

Now let’s take a closer look at how urine analysis is carried out, what types and methods of collection there are.

Express test

The fastest way to test your urine is a rapid test. It is carried out as part of routine examinations (in the family doctor's office or upon admission to the hospital) or when patients experience pain in the abdomen, stomach or back. This analysis can be done using a special strip with small colored fields, which needs to be immersed in a vessel for a few seconds. Then the doctor compares the color of the urine with the color of the fields and determines its condition. Only a specialist can determine what concentration of liquid indicates its deviation from the norm.

The test will help identify the following problems:

• high protein levels, which becomes a sign of nephritis (kidney inflammation);
• detection of sugar and ketones in the urine is a sign of high blood sugar;
• leukocytes and nitrites indicate the appearance of a bacterial infection.

It is important to note that this test is not always reliable, so it is best to have the test done in a laboratory.

Clinical (general) study

This type of analysis is part of a routine examination or performed before admission to the hospital. It is mainly used to find the cause of liver disease, kidney disease, urinary tract infections and bleeding in the urinary system. It can also be used to check for an incorrect rapid test result. A complete analysis is carried out in the laboratory, usually in 3 stages:

1. Assessment of urine color and concentration (physical indicators).
2. A study of the chemical composition of the fluid, which includes several additional tests for pH, protein, glucose, ketones, blood, bilirubin, nitrites, urobilinogen and
3. Specialists diagnose types of urine tests for bacteria under a microscope.

The results of the research also help to identify the following problems:

• high blood cholesterol levels;
• detection of urinary reflux will indicate the development of kidney diseases;
• In addition, quantitative urine tests can be performed to help diagnose a variety of specific disorders, such as endocrine diseases, bladder cancer, osteoporosis, and porphyria (a group of disorders caused by chemical imbalances).

If the doctor reveals any deviations from the norm during a clinical examination, then he recommends the following types of urine tests for infections to the patient: Nechiporenko analysis and Zimnitsky analysis.

Analysis according to Nechiporenko

These are laboratory tests that are carried out to determine the content of white blood cells, red blood cells and casts in 1 ml of urine to assess the health of the urinary tract and kidneys. This type of analysis is prescribed for the following indications:

• hidden hematuria (blood in the urine);
• monitoring the effectiveness of treatment;
• hidden inflammation in the kidneys and urinary tract.

The Nechiporenko analysis is more specific than other types of urine tests. Let's look at how to collect material below:

• the day before you should refrain from drinking alcohol, vegetables and fruits, which change the color of urine;
• before collection you need to purchase hygiene procedures;
• no more than 20-30 ml of morning urine should be collected in a prepared clean and dry container;
• It must be brought to the laboratory within 2 hours.

Normal indicators:

• leukocytes - 2000 in 1 ml of urine;
• red blood cells - 1000;
• cylinders - 20.

Urine analysis according to Zimnitsky

This type of research is unique. It helps to assess the condition of the kidneys and identify the failure of these organs at an early stage, as well as monitor the dynamics of the disease.

Indications for this type of study:

• chronic glomerulonephritis;
• diabetes;
• signs of renal failure;
• hypertensive heart disease;
• chronic pyelonephritis (kidney inflammation).

Of course, urine tests, types, and collection methods differ for each diagnosis. You need to be extremely careful when collecting material for research on Zimnitsky. You must prepare eight clean jars and label each one with the number of urinations (1, 2, 3, and so on). Collection must begin at 6.00 am, and then every three hours. Remember that pouring urine into one container is strictly prohibited. Refrigerate containers prior to transport to the laboratory. Try to maintain your normal routine and diet on this day. Do not forget to maintain good hygiene to prevent harmful bacteria and germs from getting into the jars.

Study results in case of deviation from the norm:

• a decrease in relative per serving (below 1020 g/l) indicates renal and heart failure, exacerbation of pyelonephritis;
• high density (over 1035 g/l) can occur with accelerated breakdown of red blood cells, chronic or acute glomerulonephritis, as well as diabetes.

Analysis according to Kakovsky-Addis. Amburger method

As a rule, these types of urine tests are performed on children, since they are convenient to use even for children under 3 years of age. Prescribed to patients when abnormalities are detected in a general test, if there is a suspicion of kidney and urinary tract diseases, as well as for detailed monitoring of the course of an already identified disease.

The research results help to identify the occurrence of inflammatory processes (cystitis, glomerulonephritis and pyelonephritis), as well as monitor the functioning of the kidneys and urinary tract.

Material for analysis is collected in two ways:

• within 12 hours;
• throughout the day.

What is sowing?

What other urine tests are there? The types and methods of research are discussed in detail in our article. Cultures are done to see if there are germs or harmful bacteria and to determine their type.

In the laboratory, a jar of urine is placed in a container. Small plates containing growth medium for the microorganisms are then placed into the sample and sealed tightly. Next, the container is placed in an incubator for 2 days. If there are fungi or bacteria in the urine, they will grow noticeably during this time.

If microbes were found during the study, the patient is given the type of antibiotics needed to combat them.

Urine analysis according to Sulkovich

This type of research is used as a screening test for the early diagnosis of endocrine diseases and calcium metabolism disorders. To obtain more accurate results, doctors recommend not eating dairy and meat products, fruits and vegetables, and not drinking tea and coffee before the analysis. Try to include only cereals cooked in water in your diet.

• Do not eat food for 8 hours, for children - 6 hours;
• take care of genital hygiene so that microbes do not get into the urine sample;
• the material should be collected in a sterile container and taken to the hospital.

In laboratory conditions, specialists will add Sulkovich's reagent to the urine, which will help determine the amount of calcium and bilirubin.

Daily analysis

This test consists of collecting urine during the day in the following sequence:

• the first sample after waking up is not used, but the time of urination is noted;
• after that, each drop of material is collected in a jar;
• when you have emptied your bladder within 24 hours, you need to take a special container from your doctor, in which a substance has already been placed to prevent the growth of bacteria, and pour all the collected liquid into it;
• Keep the jar in the refrigerator during collection.

Diagnostic results show how much of certain substances (such as proteins, hormones, salts and other metabolic products) are excreted from the body. If specialists find too little metabolic creatinine in the urine, then a suspicion arises of a decrease in kidney function. High protein levels can be caused by heart failure, diabetes, urinary tract infection, and kidney disease. Some endocrine system disorders increase the amount of hormones and their metabolic products in the urine.

Pregnancy test

Of course, these types of urine tests are performed on women. If your menstrual cycle does not start, tests can be used to check if you are pregnant. Most studies can determine this as early as the tenth day of conception. However, they are not always reliable. You can buy tests at any pharmacies.

These types of urine tests are performed during pregnancy, usually in the morning, after waking up. Please refer to the package insert for exact instructions. After urinating, collect a small amount of morning urine in a container and dip the test stick into it for a few seconds. After five minutes it will show whether you are pregnant or not.

It is important to note that test results can sometimes be false. This happens when a woman has it too early, takes specific medications, or drinks too much liquid before the test. Only a doctor can tell you for sure whether you are pregnant or not.

urine in children

Doctors may order a urine test for your child for various reasons. As a rule, these are preventive purposes, the occurrence of abnormalities in a general urine test or the control of an already detected disease.

Let's look at the main types of urine tests in children:

• General (clinical) urine examination.
• Nechiporenko test.
• Analysis according to Zimnitsky.
• Diagnosis according to Kakovsky-Addis.
• Amburger's technique.
• Bacteriological culture of urine.
• Rehberg's test.

Types of urine tests during pregnancy

From the moment a pregnant woman registers with a gynecologist, she will be advised to undergo a general urine test throughout her pregnancy. If any abnormalities are detected in this study, the doctor will advise you to conduct a urine test according to Nechiporenko or Zimnitsky, as well as bacteriological tests to detect infections.

Such monitoring will help the specialist assess the condition of the bladder, determine kidney disease, and the onset of diabetes mellitus and gestational diabetes, which can develop in the twentieth week of pregnancy. High levels of protein will indicate inflammation of the urinary tract. Elevated ketone levels indicate that a woman's body is dehydrated. It is not recommended for pregnant women to perform a urine test on their own. All actions should be discussed with your doctor.

Conclusion

To summarize, we can draw conclusions:

• urine analysis, types and methods of collection are completely different, and they should be carried out only on the recommendation of a doctor;
• some studies can be done independently, for example, a rapid test and a pregnancy test;
• other types of diagnostics are carried out exclusively in the laboratory to detect any abnormalities;
• To reduce the chance of urine becoming contaminated with bacteria, practice good hygiene.

Urine is a metabolic product formed in the kidneys as a result of filtration of the liquid part of the blood, as well as the processes of reabsorption and secretion of various analytes. It consists of 96% water, the remaining 4% comes from nitrogenous products of protein metabolism dissolved in it (urea, uric acid, creatinine, etc.), mineral salts and other substances.

A general urine test in children and adults includes assessment of the physicochemical characteristics of urine and sediment microscopy. This study allows you to evaluate the function of the kidneys and other internal organs, as well as identify the inflammatory process in the urinary tract

Physicochemical studies of urine include assessment of the following indicators:

• color;
• urine clarity;
• specific gravity (relative density);
• protein concentration;
• glucose concentration;
• bilirubin concentration;
• urobilinogen concentration;
• concentration of ketone bodies;
• nitrite concentration;
• hemoglobin concentration.

Microscopy of urinary sediment includes assessment of the following objects:

The assessment of the physical properties of urine, such as odor, color, turbidity, is carried out using the organoleptic method. The specific gravity of urine is measured using a urometer, a refractometer, or assessed using “dry chemistry” methods (test strips) - visually or on automatic urine analyzers.

Urine color

An adult's urine is yellow. Its shade can vary from light (almost colorless) to amber. The saturation of the yellow color of urine depends on the concentration of substances dissolved in it. With polyuria, urine has a lighter color; with a decrease in diuresis, it acquires a rich yellow tint. The color changes when taking medications (salicylates, etc.) or eating certain foods (beets, blueberries).

Pathologically changed color of urine occurs when:

• hematuria – a type of “meat slop”;
• bilirubinemia (beer color);
• hemoglobinuria or myoglobinuria (black);
• leukocyturia (milky white color).

Urine clarity

Normally, freshly collected urine is completely clear. Turbidity of urine is due to the presence in it of a large number of cellular formations, salts, mucus, bacteria, and fat.

Urine smell

Normally, the smell of urine is not strong. When urine decomposes by bacteria in the air or inside the bladder, for example in the case of cystitis, an ammonia odor appears. Rotted urine that contains protein, blood, or pus, such as from bladder cancer, causes the urine to smell like rotten meat. If there are ketone bodies in the urine, the urine has a fruity odor, reminiscent of the smell of rotting apples.

Urine reaction

The kidneys excrete “unnecessary” substances from the body and retain necessary substances to ensure the exchange of water, electrolytes, glucose, amino acids and maintain acid-base balance. The reaction of urine - pH - largely determines the effectiveness and characteristics of these mechanisms. Normally, the urine reaction is slightly acidic (pH 5.0–7.0). It depends on many factors: age, diet, body temperature, physical activity, kidney condition, etc. The lowest pH values ​​are in the morning on an empty stomach, the highest are after meals. When eating mainly meat foods, the reaction is more acidic, when eating plant foods, the reaction is alkaline. When standing for a long time, urine decomposes, ammonia is released and the pH shifts to the alkaline side.

An alkaline urine reaction is characteristic of chronic urinary tract infection and is also observed with diarrhea and vomiting.

The acidity of urine increases in feverish conditions, diabetes mellitus, tuberculosis of the kidneys or bladder, and renal failure.

Specific gravity (relative density) of urine

Relative density reflects the functional ability of the kidneys to concentrate and dilute urine. Normally functioning kidneys are characterized by wide fluctuations in the specific gravity of urine during the day, which is associated with periodic intake of food, water and fluid loss from the body. The kidneys under various conditions can excrete urine with a relative density of 1.001 to 1.040 g/ml.

There are:

• hyposthenuria (fluctuations in the specific gravity of urine less than 1.010 g/ml);
• isosthenuria (the appearance of a monotonous specific gravity of urine corresponding to that of primary urine (1.010 g/ml);
• hypersthenuria (high specific gravity values).

The maximum upper limit of the specific gravity of urine in healthy people is 1.028 g/ml, in children – 1.025 g/ml. The minimum lower limit for urine specific gravity is 1.003–1.004 g/ml.

To assess the chemical composition of urine, diagnostic test strips (the “dry chemistry” method), produced by different manufacturers, are currently usually used. The chemical methods used in test strips are based on color reactions that produce a change in the color of the test area of ​​the strip at different concentrations of the analyte. Discoloration is determined visually or by reflectance photometry using semi-automated or fully automated urine analyzers, and the results are assessed qualitatively or semi-quantitatively. If a pathological result is detected, the study can be repeated using chemical methods.

Protein

Protein is normally absent in urine or present in concentrations undetectable by conventional methods (traces). Several types of proteinuria (the appearance of protein in the urine) are identified:

• physiological (orthostatic, after increased physical activity, hypothermia);
• glomerular (glomerulonephritis, the action of infectious and allergic factors, hypertension, cardiac decompensation);
• tubular (amyloidosis, acute tubular necrosis, interstitial nephritis, Fanconi syndrome).
• prerenal (myeloma, muscle tissue necrosis, erythrocyte hemolysis);
• postrenal (for cystitis, urethritis, colpitis).

Glucose

Normally, there is no glucose in the urine. The appearance of glucose in the urine can have several reasons:

• physiological (stress, intake of increased amounts of carbohydrates);
• extrarenal (diabetes mellitus, pancreatitis, diffuse liver damage, pancreatic cancer, hyperthyroidism, Itsenko-Cushing's disease, traumatic brain injury, stroke);
• renal (renal diabetes, chronic nephritis, acute renal failure, pregnancy, phosphorus poisoning, certain medications).

Bilirubin

Bilirubin is normally absent in urine. Bilirubinuria is detected in parenchymal liver lesions (hepatitis), obstructive jaundice, cirrhosis, cholestasis, as a result of the action of toxic substances.

Urobilingen

Normal urine contains low concentrations (traces) of urobilinogen. Its level increases sharply with hemolytic jaundice, as well as with toxic and inflammatory lesions of the liver, intestinal diseases (enteritis, constipation).

Ketone bodies

Ketone bodies include acetone, acetoacetic and beta-hydroxybutyric acids. An increase in the excretion of ketones in the urine (ketonuria) occurs when carbohydrate, lipid or protein metabolism is disturbed.

Nitrites

There are no nitrites in normal urine. In urine, they are formed from nitrates of food origin under the influence of bacteria, if the urine was in the bladder for at least 4 hours. The detection of nitrites in properly stored urine samples indicates infection of the urinary tract.

Hemoglobin

Normally absent in urine. Hemoglobinuria - the result of intravascular hemolysis of red blood cells with the release of hemoglobin - is characterized by the release of red or dark brown urine, dysuria, and often lower back pain. With hemoglobinuria, there are no red blood cells in the urine sediment.

Microscopy of urine sediment

Urine sediment is divided into organized (elements of organic origin - red blood cells, leukocytes, epithelial cells, casts, etc.) and unorganized (crystals and amorphous salts).

Research methods

The study is carried out visually in the native preparation using a microscope. In addition to visual microscopic examination, research using automatic and semi-automatic analyzers is used.

Red blood cells

During the day, 2 million red blood cells are excreted in the urine, which, when examining urine sediment, is normally 0–3 red blood cells per field of view for women and 0–1 red blood cells per field of view for men. Hematuria is an increase in red blood cells in the urine above the specified values. There are macrohematuria (the color of urine is changed) and microhematuria (the color of urine is not changed, red blood cells are detected only by microscopy).

In urinary sediment, red blood cells can be unchanged (containing hemoglobin) and changed (deprived of hemoglobin, leached). Fresh, unchanged red blood cells are characteristic of urinary tract lesions (cystitis, urethritis, stone passage).

The appearance of leached red blood cells in the urine is of great diagnostic importance, because they are most often of renal origin and occur in glomerulonephritis, tuberculosis and other kidney diseases. To determine the source of hematuria, a three-glass sample is used. When bleeding from the urethra, hematuria is greatest in the first portion (unchanged red blood cells), from the bladder - in the last portion (unchanged red blood cells). With other sources of bleeding, red blood cells are distributed evenly in all three portions (leached red blood cells).

Leukocytes

Leukocytes are found in small quantities in the urine of a healthy person. The norm for men is 0–3, for women and children 0–6 leukocytes per field of view.

An increase in the number of leukocytes in the urine (leukocyturia, pyuria) in combination with bacteriuria and the presence of clinical symptoms indicates inflammation of an infectious nature in the kidneys or urinary tract.

Epithelial cells

Epithelial cells are almost always found in urinary sediment. Normally, a urine test shows no more than 10 epithelial cells per field of view.

Epithelial cells have different origins:

• squamous epithelial cells enter the urine from the vagina, urethra, their presence has no special diagnostic significance;
• transitional epithelial cells line the mucous membrane of the bladder, ureters, pelvis, and large ducts of the prostate gland. The appearance of a large number of such epithelial cells in the urine can be observed with urolithiasis, neoplasms of the urinary tract and inflammation of the bladder, ureters, pelvis, large ducts of the prostate gland;
• renal epithelial cells are detected in cases of damage to the kidney parenchyma, intoxication, febrile, infectious diseases, and circulatory disorders.

Cylinders

The cylinder is a protein that is coagulated in the lumen of the renal tubules and includes in its matrix any contents of the lumen of the tubules. The cylinders take the shape of the tubules themselves (cylindrical cast). Normally, there are no casts in a urine sample taken for general analysis. The appearance of casts (cylindruria) is a symptom of kidney damage.

Cylinders are distinguished:

• hyaline (with overlay of erythrocytes, leukocytes, renal epithelial cells, amorphous granular masses);
• granular;
• waxy;
• pigmented;
• epithelial;
• erythrocyte;
• leukocyte;
• fatty.

Unorganized sediment

The main component of unorganized urine sediment is salts in the form of crystals or amorphous masses. The nature of the salts depends on the pH of the urine and other properties of the urine. For example, with an acidic reaction of urine, uric acid, urates, oxalates are detected, with an alkaline reaction of urine - calcium, phosphates, ammonium urate. Disorganized sediment does not have any particular diagnostic significance; one can indirectly judge the patient’s propensity for urolithiasis. In a number of pathological conditions, crystals of amino acids, fatty acids, cholesterol, bilirubin, hematoidin, hemosiderin, etc. may appear in the urine.

The appearance of leucine and tyrosine in the urine indicates a severe metabolic disorder, phosphorus poisoning, destructive liver disease, pernicious anemia, and leukemia.

Cystine is a congenital disorder of cystine metabolism - cystinosis, liver cirrhosis, viral hepatitis, hepatic coma, Wilson's disease (congenital defect of copper metabolism).

Xanthine – xanthinuria is caused by the absence of xanthine oxidase.

Bacteria

Normally, urine in the bladder is sterile. When urinating, germs from the lower urethra enter it.

The appearance of bacteria and leukocytes in a general urine analysis against the background of symptoms (dysuria or fever) indicates a clinically manifested urinary infection.

The presence of bacteria in the urine (even in combination with leukocytes) in the absence of complaints is regarded as asymptomatic bacteriuria. Asymptomatic bacteriuria increases the risk of urinary tract infection, especially during pregnancy.

Yeast mushrooms

The detection of fungi of the genus Candida indicates candidiasis, which most often occurs as a result of irrational antibiotic therapy, the use of immunosuppressants, and cytostatics.

In the urine sediment, blood schistosome eggs (Schistosoma hematobium), elements of the echinococcal bladder (hooks, scolex, brood capsules, fragments of the bladder shell), migrating larvae of intestinal eels (strongylides), washed off with urine from the perineum of the oncosphere of taeniids, pinworm eggs (Enterobius vermicularis) can be found ) and pathogenic protozoa - Trichomonas (Trichomonas urogenitalis), amoebas (Entamoeba histolitika - vegetative forms).

Conditions for sample collection and storage

For general analysis, morning urine is collected. Urine collection is carried out after thorough toileting of the external genitalia without the use of antiseptics. For the study, freshly collected urine is used, stored until analysis for no more than four hours. Samples are stable at temperatures of 2–8 °C for no more than 2 days. The use of preservatives is undesirable. Before the study, the urine is thoroughly mixed.

Reading time: 11 min.

The kidneys are a paired organ with a fine structure, so the slightest change in the normal course of any internal processes leads to noticeable deviations in the performance of the urinary system.

Pathologies of the kidneys, urinary tract and some other organs can be determined by a general urine test (abbreviated to OAM on medical forms). It is also called clinical.

• Show all

  1. Why is this test prescribed?

  Urine is a biological fluid in which the final waste products of the body are released from the human body.

  It is conventionally divided into primary (formed by filtration in the glomeruli from blood plasma) and secondary (formed by reabsorption of water, necessary metabolites and other solutes in the renal tubules).

  Disruption of this system entails characteristic changes in normal TAM indicators. Thus, the analysis can show:

  1. 1 Deviations in metabolism;
  2. 2 Signs of urinary tract infection;
  3. 3 Effectiveness of treatment and diet;
  4. 4 Dynamics of recovery.

  A person can contact a laboratory for a urine test on his own initiative if he notices sudden changes in his physical characteristics. But more often the patient receives a referral from a specialist at the clinic, who then deciphers the results obtained.

  OAM is included in the list of basic studies during preventive examinations of the population, clinical examination, it is prescribed when seeking medical help from a specialist, during pregnancy, during hospitalization and in some other cases.

  A general urine test consists of a sequential study of:

  1. 1 Physical characteristics of the sample;
  2. 2 Chemical composition;
  3. 3 Microscopic examination of sediment.

  2. Patient preparation

  Before submitting the material for general (clinical) analysis, consult your doctor about the possible temporary cessation of taking certain pharmaceutical drugs. For example, diuretics should be stopped 48 hours before sample collection.

  Women should remember that menstruation usually skews the results. For testing, it is better to choose a time before your period or two days after the end of the discharge.

  The day before collecting biomaterial, avoid foods with a high content of pigments, alcohol, fatty, smoked foods, sex, and excessive physical and psycho-emotional stress. All this can distort the OAM results.

  For analysis, a morning urine sample is collected, optimally its middle part. Before collection, the patient must toilet the external genitalia (bath, shower, wet wipes).

  After the start of urination, it is better to flush the first portion into the toilet, collect the middle portion in a clean, sterile container (optimally in a sterile pharmaceutical container). The minimum volume of urine required for testing is 50 ml. There is a mark on the medicine cup to the level at which it is advisable to fill the container.

  In young children, it is often difficult to collect urine for analysis. Therefore, when collecting, you can use small tricks:

  1. 1 Buy special soft polyethylene containers with a sticky edge at the pharmacy. Not all children like this procedure, but for some it is acceptable.
  2. 2 Before picking up, take the baby to the bathroom and turn on the water. A child up to one year old can be breastfed beforehand, and an older baby can be given water to drink. Urination in babies is tied to feeding, so the task can be made easier.
  3. 3 Some children pee several times with intervals between peeings of 10-15 minutes. To collect material from such babies, it is better to prepare several containers so that you can collect the droplets in different dishes without staining them during manipulation.
  4. 4 Before the procedure, you can do a soft, stroking massage in the lower abdomen, in the bladder area.

  3. What should not be done when collecting urine?

  When collecting material for clinical urine analysis, it is not recommended:

  1. 1 Use untreated dishes, contents of a potty, diaper, diaper, plastic bag. This analysis is called “dirty”; it is not suitable for assessing the condition of the urinary system.
  2. 2 Use for analysis stale urine that has stood for more than 3 hours or has been in the refrigerator without a special preservative.
  3. 3 Collect material for OAM after defecation, during menstruation or after sexual intercourse.
  4. 4 Collect material for research during acute inflammatory diseases of the reproductive system, skin around the urethra and vagina (you must warn the doctor about this in advance). It will not be possible to collect such an analysis purely.
  5. 5 Do not use a urinary catheter unless there is an urgent need for it (prostate cancer, prostate adenoma, a bedridden seriously ill patient and other situations that are specified by the attending physician). When placing a catheter at home, there is a high risk of secondary infection.

  The table below presents the main indicators, their standards and interpretation. Clinical urine analysis in women is practically no different from that in men, with the exception of some parameters. These small nuances are noted in the table.

  Index	Decoding	Norm
  BLd	Red blood cells	2-3 in the field of view in women (abbreviated as p/z) / Single in men
  LEU	Leukocytes	3-6 in p/z for women / Up to 3 - for men
  Hb	Hemoglobin	Absent (sometimes they write the abbreviation neg - negative)
  BIL	Bilirubin	Absent (neg)
  UBG	Urobilinogen	5-10 mg/l
  PRO	Protein	Absent or up to 0.03 g/l
  NIT	Nitrites	Absent
  G.L.U.	Glucose	Absent
  KET	Ketone bodies	Absent
  pH	Acidity	5-6
  S.G.	Density	1012-1025
  COLOR	Color	Light yellow

  Table 1 - Indicators assessed in clinical urine analysis

  4. Physical properties

  4.1. Quantity

  When assessing the total amount of urine excreted, it is necessary to take into account the possible dietary characteristics of each patient. In an adult who follows a normal diet, daily diuresis ranges from 800 to 1500 ml.

  Diuresis directly depends on the volume of fluid drunk. Typically, 60-80% of what you consume per day is excreted from the body. The normal ratio of daytime to nighttime diuresis is 3:1 or 4:1.

  A condition characterized by increased urine output (more than 2000 ml per day) is called polyuria.

  A similar phenomenon is observed normally:

  1. 1 If you have drunk a lot over the past day;
  2. 2 With nervous excitement or overexertion.

  Polyuria can be observed in the following pathological conditions:

  1. 1 Kidney diseases (CKD, stage of resolution of acute renal failure);
  2. 2 Relief of edema, for example, against the background of diuretics;
  3. 3 Diabetes insipidus and diabetes mellitus;
  4. 4 Nephropathies (amyloidosis, myeloma, sarcoidosis);
  5. 5 Taking certain medications.

  The reverse condition is called oliguria. With oliguria, less than 500 ml of urine is excreted per day.

  Physiologically it can occur with:

  1. 1 Reduce fluid intake;
  2. 2 Loss of fluid through sweat in the heat;
  3. 3 Significant physical activity.

  It is noted in the following pathologies:

  1. 1 Cardiac decompensation;
  2. 2 Poisoning;
  3. 3 Excessive loss of water from the body (for example, during profuse diarrhea, vomiting);
  4. 4 Burns;
  5. 5 Shock conditions;
  6. 6 Fever of any origin;
  7. 7 Kidney damage of infectious, autoimmune and toxic origin.

  Anuria is a condition in which urine production stops completely.. Anuria is typical for:

  1. 1 Initial stage of acute renal failure;
  2. 2 Acute blood loss;
  3. 3 Uncontrollable vomiting;
  4. 4 Stones in the urinary tract with obstruction of the lumen;
  5. 5 Oncological diseases accompanied by obstruction and compression of the ureters.

  Nocturia is a condition in which nocturnal diuresis significantly prevails over daytime. Nocturia is typical for:

  1. 1 Diabetes insipidus and diabetes mellitus;
  2. 2 Many kidney diseases;

  4.2. Urinary frequency

  In addition to the daily amount of urine, pay attention to the frequency of urination. Normally, this process is performed by a person 4-5 times during the day.

  Pollakiuria is characterized by frequent trips to the toilet. Observed when:

  1. 1 Drink plenty of liquid;
  2. 2 Urinary infections.

  Olakiuria is the opposite condition to that described above. Characteristic for:

  1. 1 Low intake of fluid into the body;
  2. 2 Neuro-reflex disorders.

  Strangury is painful urination.

  Dysuria is a urination disorder that combines symptoms such as changes in urine volume, frequency and pain. She usually accompanies.

  4.3. Color

  Is a direct reflection of concentration. In a healthy person, deviations in color from straw yellow to amber are allowed.

  The color of urine is also influenced by special substances, the basis of which are blood pigments. A dark yellow color is observed when the amount of coloring substances dissolved in it significantly exceeds the norm. Characteristic of such conditions:

  1. 1 Edema;
  2. 2 Vomiting;
  3. 4 Burns;
  4. 4 Stagnant kidney;
  5. 5 Diarrhea.
  1. 1 Diabetes mellitus;
  2. 2 Diabetes insipidus.

  The dark brown color is explained by an increase in the level of urobilinogen. It is a diagnostic criterion for hemolytic anemia. Urine may turn dark brown when taking sulfonamides.

  Dark, practical black color can indicate several conditions:

  1. 1 Alkaptonuria (due to homogentisic acid);
  2. 2 Acute hemolytic kidney;
  3. 3 Melanosarcoma (obtains this shade due to the presence of melanin).

  Urine turns red if it contains fresh blood or red pigments. This is possible with:

  1. 1 Kidney infarction;
  2. 2 Renal failure;
  3. 3 Damage and trauma to the urinary tract;
  4. 4 Taking certain medications (for example, rifampicin, adriamycin, phenytoin).

  The appearance of “meat slop” is explained by the presence of altered blood, which is characteristic of acute glomerulonephritis.

  A greenish-brown tint (compared to the color of beer) appears if bilirubin and urobilinogen enter the urine. This deviation from the norm often indicates parenchymal jaundice.

  If the shade is rather greenish-yellow, which may indicate the presence of bilirubin alone, and is considered a symptom of obstructive jaundice.

  4.4. Transparency

  Normally, urine is clear. However, in the presence of pathological components and impurities (proteins, leukocytes, erythrocytes, epithelium, bacteria, salts), it can be cloudy, cloudy and milky.

  Several manipulations can be carried out in advance to narrow the range of possible substances that make up the sediment to certain salts.

  When, when heated, the test tube with the test material becomes transparent again, we can conclude that it contained urates.

  If the same happens upon contact with acetic acid, we can assume the presence of phosphates in the sample. If an identical effect is observed when mixed with hydrochloric acid, then there are .

  For more accurate data, microscopy of the sediment is performed.

  4.5. Smell

  The smell of urine is usually specific and not strong. An ammonia odor may appear if there is bacterial contamination of the sample. A fruity smell (of rotting apples) is considered an indicator of the presence of ketone bodies.

  4.6. Relative density (SG)

  This indicator is considered very important, since it is used to judge the concentration function of the kidneys and its ability to dilute.

  The measurement is carried out using a specially designed device - a urometer. During the study, attention is primarily paid to the content of electrolytes and urea, and not to substances with high molecular weight (proteins, glucose, etc.).

  Normally, the relative density of the morning urine portion is determined in the range from 1.012 to 1.025. During the day it can fluctuate between 1001 - 1040, therefore, if a patient is suspected of having a decrease in the concentrating ability of the kidneys, it is usually prescribed.

  Hypersthenuria – an indicator higher than normal. Its cause may be:

  1. 1 Toxicosis of pregnant women;
  2. 2 Progressive edema;
  3. 3 Nephrotic syndrome;
  4. 4 Diabetes mellitus;
  5. 5 Use of radiopaque agents.

  Hyposthenuria - decreased specific gravity. Observed in the following conditions:

  1. 1 Malignant hypertension;
  2. 2 Chronic renal failure;
  3. 3 Diabetes insipidus;
  4. 4 Damage to the kidney tubules.

  Isosthenuria is a condition in which the density of urine is equal to the density of blood plasma (within 1010-1011).

  5. Chemical properties

  This is the second group of urine indicators that characterize the patient’s health status.

  5.1. Medium reaction (pH)

  Normally, urine pH ranges between 5-7. Acid reaction (pH<5) может быть следствием:

  1. 1 Increased consumption of meat products;
  2. 2 Metabolic or respiratory acidosis (as a consequence of various pathological processes), coma;
  3. 3 Acute glomerulonephritis;
  4. 4 Gout;
  5. 5 Hypokalemia.

  An alkaline reaction (pH>7) occurs when:

  1. 1 Vegetable diet;
  2. 2 Chronic renal failure;
  3. 3 Metabolic or gas alkalosis;
  4. 4 Hyperkalemia;
  5. 5 Active inflammatory processes in the urinary system.

  5.2. Protein Determination (PRO)

  Normally, it is not detected or an insignificant amount is detected. A condition in which this threshold is exceeded is called proteinuria. It is customary to distinguish several types of proteinuria:

  1. 1 Prerenal proteinuria is associated with pathological processes in the human body that are accompanied by an increase in protein concentration in the blood plasma (myeloma, for example).
  2. 2 Renal - one that is a consequence of damage to the glomerular filter or dysfunction of the renal tubules. The diagnostic criterion for the severity of the pathological process is selectivity - the greater the number of large protein molecules found in secondary urine, the more serious the situation.
  3. 3 Postrenal proteinuria is a manifestation of inflammatory processes in the reproductive system and surrounding tissues (vulvovaginitis, balanitis, and so on).
  4. 4 Proteinuria can also be physiological, for example, during emotional overload, exposure to cold or sun, in children in a standing position, during long walking or running.

  5.3. Determination of glucose (GLU)

  Normally, this substance cannot be detected in urine due to its low content. Glucosuria is the name given to a condition in which glucose levels exceed 0.8 mmol/l. This occurs when the so-called renal glucose threshold is exceeded.

  That is, when its concentration in the blood exceeds 9.9 mmol/l, it freely passes the barrier and enters the urine. There are the following types of glucosuria:

  1. 1 Alimentary (large amounts come from food);
  2. 2 Emotional;
  3. 3 Medicinal.

  Pathological glucosuria is usually divided into renal (manifests itself in various kidney diseases) and extrarenal, which is considered a consequence of the following diseases:

  1. 1 Diabetes mellitus;
  2. 2 Thyrotoxicosis;
  3. 3 Pheochromocytomas;
  4. 4 Acute pancreatitis and other diseases of the pancreas;
  5. 5 Itsenko-Cushing's disease;
  6. 6 Cirrhosis of the liver;
  7. 7 Poisoning.

  5.4. Determination of hemoglobin (Hb)

  It is believed that hemoglobin is found in a portion of urine during the rapid breakdown (hemolysis) of red blood cells. Such a process may be infectious, immunological or genetic in nature. Most often, hemoglobinuria is detected with:

  1. 1 Hemolytic anemia;
  2. 2 Transfusion of incompatible blood;
  3. 3 Internal injuries (crash syndrome);
  4. 4 Severe poisoning;
  5. 5 Direct damage to kidney tissue.

  Hemoglobinuria is dangerous because it is an impetus for the development of acute renal failure.

  5.5. Determination of ketone bodies (KET)

  Ketonuria is a special indicator of urine analysis, which reflects the failure of metabolic processes occurring in the body. In this case, the following substances are detected: acetone, beta-hydroxybutyric, acetoacetic acids. Ketonuria occurs against the background of:

  1. 1 Diabetes mellitus;
  2. 2 Carbohydrate starvation, diets;
  3. 3 Severe toxicosis (more often in children);
  4. 4 Dysentery;
  5. 5 Severe CNS irritation;
  6. 6 Overproduction of corticosteroids.

  5.6. Determination of bilirubin (BIL)

  Bilirubinuria is a pathological condition in which unchanged bilirubin is detected in the urine. When the mechanisms that utilize bilirubin fail, the kidneys take on part of the work. Bilirubinuria is typical of many liver diseases:

  1. 1 Cirrhosis;
  2. 2 Hepatitis;
  3. 3 Jaundice (parenchymal and mechanical);
  4. 4 Gallstone disease.

  5.7. Determination of urobilin bodies (UBG)

  Urobilinuria occurs when the liver does not function properly. However, intestinal pathology (where this substance is formed) and processes leading to the breakdown of red blood cells also contribute to the appearance of urobilinogen in the urine.

  A high content of urobilinogen bodies in the sample (UBG in the analysis form) is detected when:

  1. 1 Hepatitis;
  2. 2 Sepsis;
  3. 1 Hemolytic anemia;
  4. 4 Cirrhosis;
  5. 5 Intestinal diseases (inflammation, obstruction).

  6. Microscopic examination of sediment

  Microscopic examination of organized and unorganized urine sediment is of great importance in diagnosis. For this purpose, the laboratory technician lets the resulting sample sit for about two hours, then centrifuges it, drains the liquid, and examines a drop of sediment under a microscope.

  At low magnification, the cylinders within the field of view are counted, and at high magnification, leukocytes, erythrocytes and other cellular elements are counted.

  Counting the number of cellular elements in a material greatly facilitates the use of Goryaev’s camera.

  6.1. Red blood cells (BLD)

  Normally there are, but their number is limited to one cell in the field of view in men and up to three in women).

  – a condition in which more red blood cells are found in the urine. There are macrohematuria (the presence of blood clots can be determined with the naked eye) and microhematuria (the presence of red blood cells can only be detected using a microscope).

  

  Figure 1 - Changed erythrocytes in urine under a microscope, native preparation. Source Masaryk University (https://is.muni.cz/do/rect/el/estud/lf/js15/mikroskop/web/pages/zajimave-nalezy_en.html)

  In addition, glomerular (renal) hematuria is distinguished, which manifests itself in kidney diseases of various origins, medicinal and toxic damage to the renal tissue, and non-glomerular, which is associated with the inflammatory process, injuries and oncological diseases.

  

  Figure 2 - Unchanged erythrocytes (native preparation, red arrow indicates erythrocyte and leukocyte). Source Masaryk University

  6.2. Leukocytes (LEU)

  In a healthy man, leukocytes in the urine are represented by a small number of neutrophils (up to three), in women there are slightly more of them (up to six).

  An increase in the level of white blood cells in the urine is called leukocyturia. This always indicates inflammatory processes in the kidneys or urinary tract, such as:

  1. 2 Glomerulonephritis;
  2. 3 Kidney tuberculosis;
  3. 5 Urethritis;
  4. 6 Fever.

  If among all the cells there are noticeably more eosinophils, then they talk about the allergic genesis of the disease, if there are lymphocytes - about the immunological one.

  

  Figure 3 - Leukocytes in urine under a microscope

  6.3. Epithelium

  Normally, microscopy reveals up to 5-6 cells. However, the elements should be distinguished from each other, since they reflect different clinical manifestations:

  1. 1 Flat epithelium enters the material from the external genitalia. Often observed with urethritis in men, in poorly collected samples in women.
  2. 2 Transitional epithelium is part of the mucous membrane of the urinary tract. Found in cystitis, neoplasms, pyelitis.
  3. 3 Renal epithelium, present in large quantities in TAM, indicates the following conditions: acute and chronic kidney damage, intoxication, fever, infection.

  6.4. Cylinders

  These are protein or cellular elements originating from the tubular epithelium.

  1. 1 Hyaline (protein) appear when:
     • dehydration of the body;
     • nephropathy in pregnant women;
     • fevers;
     • poisoning with salts of heavy metals.
  2. 2 Waxy (protein) speaks of:
     • nephrotic syndrome;
     • amyloidosis.
  3. 3 Cellular casts can indicate problems of a very wide etiology and are a direct indication of more detailed analyzes.

  6.5. Slime

  Normally found in small quantities. At higher levels, mucus may indicate the following diseases:

  1. 5 Urethritis;
  2. 4 Kidney stone disease;
  3. 5 Incorrect sample collection.
  G.L.U.GlucoseAbsent KETKetone bodiesAbsent pHAcidity5-6 S.G.Density1012-1025 COLORColorLight yellow

Bibliography

1. 1 Kozinets G.I. Interpretation of blood and urine tests and their clinical significance / G.I. Kozinets. - M.: Triad X, 1998. – 100 p.;
2. 2 Yurkovsky O.I. Clinical analysis in medical practice / O.I. Yurkovsky, A.M. Gritsyuk. – K.: Technology, 2000. – 112 p.;
3. 3 Medvedev V.V. Clinical laboratory diagnostics: Doctor's reference book/ V.V. Medvedev, Yu.Z. Volchek / Edited by V.A. Yakovleva. – St. Petersburg: Hippocrates, 2006. – 360 pp.;
4. 4 Zupanets I.A. Clinical laboratory diagnostics: research methods: Textbook. manual for students special. “Pharmacy”, “Wedge. Pharmacy", "Lab. Diagnostics" of universities /I.A. Zupanets, S.V. Misyurova, V.V. Propisnova et al.; Ed. I.A Zupanca – 3rd ed., revised. and additional – Kharkov: NUPh Publishing House: Golden Pages, 2005. – 200 pp.; 12 s. color on;
5. 5 Morozova V.T. Urine examination: Textbook. allowance / V.T. Morozova, I.I. Mironova, R.L. Shartsinevskaya. – M.: RMAPO, 1996. – 84 p.

Clinical task on the topic of the article:

A 45-year-old man visited a nephrologist for examination regarding microhematuria. Microhematuria was first identified 6 months ago (the patient changed jobs and underwent a medical examination for health insurance), which was reported to him twice in the last six months by his attending physician.

Previous urine tests did not reveal any pathological changes. The patient has never reported gross hematuria (red-colored urine, blood in the urine), has not experienced any urinary tract symptoms, and currently feels in excellent shape.

There is no history of serious illnesses, no symptoms of visual or hearing impairment. There is no mention of kidney disease in relatives in the family history. According to the patient, he drinks about 200 grams of vodka a week and smokes 30 cigarettes a day.

Inspection data

The patient has no signs of being overweight. Pulse – 70 beats per minute, blood pressure – 145/100 mmHg. An examination of the cardiovascular, respiratory, nervous systems, and abdominal organs did not reveal any abnormalities.

Fundoscopy (examination of the fundus) revealed tortuous arteries and veins of the fundus, perpendicular branching of the retinal arteries.

Research results

Questions

1. 1 Most likely diagnosis.
2. 2 What further tests should be ordered?
3. 3 What recommendations should be given to the patient?
4. 4 How to interpret the results of a biochemical blood test?

Problem solving and patient management tactics

Microscopic hematuria can occur as a result of a wide range of pathologies (for example, prostate diseases, urolithiasis), but its combination with arterial hypertension, proteinuria (increased protein in the urine), impaired renal function (increased levels of creatinine and urea) indicates that the patient has chronic glomerulonephritis.

An increase in the level of GGTP in a biochemical analysis may indicate liver damage as a result of chronic alcohol consumption (here it is necessary to clarify the life history of this patient).

The most common causes of microhematuria:

1. 1 Chronic glomerulonephritis, including immunoglobulin A (Ig A) nephropathy;
2. 2 Thin basement membrane disease (benign hematuria);
3. 3 Alport syndrome.

Ig A nephropathy, the most common glomerulonephritis in developed countries, is characterized by diffuse mesangial deposits of IgA.

Patients often experience episodes of gross hematuria (red urine) in response to the development of inflammatory diseases of the upper respiratory tract.

In most cases, the triggering factor of the disease cannot be identified. There is often an association with Henoch-Schönlein purpura and other autoimmune diseases, alcoholic cirrhosis of the liver, infections, and oncology.

In this patient, immunoglobulin nephropathy may be combined with alcoholic liver disease, which requires clarification. 2 out of 10 patients with IgA nephropathy develop end-stage chronic renal failure within 20 years.

Thin basement membrane disease is a hereditary disease that is accompanied by the determination of red blood cells, protein in the urine (minimal proteinuria), and normal kidney function tests that do not deteriorate over time.

Electron microscopy reveals diffuse thinning of the glomerular basement membranes (normally the thickness of the basement membrane is 300–400 nm, while in patients with benign hematuria the thickness of the glomerular basement membranes is 150–225 nm).

Alport syndrome is a progressive hereditary disease (the gene is inherited on the X chromosome in a dominant manner, men are more often affected) of the glomeruli of the kidneys, which is associated with deafness and visual impairment.

This patient needs to undergo a kidney biopsy for histological verification and an accurate diagnosis.

Since the patient is over 40 years old, it is necessary to conduct a PSA test, transrectal digital examination (to exclude prostate cancer), and if bladder cancer is suspected, urine cytology, ultrasound, and cystoscopy of the bladder.

To assess the condition of the liver, it is necessary to perform an ultrasound examination and, if necessary, decide on a liver biopsy.

The patient should be advised to stop drinking alcohol and regularly monitor blood pressure. The patient should be regularly examined by a nephrologist, as he is at high risk for the progression of renal failure, with a high probability of undergoing hemodialysis and/or kidney transplantation.

The patient should be referred to a cardiologist for blood pressure profiling and antihypertensive therapy.

Moderately elevated creatinine levels indicate glomerular damage. Currently, there is no convincing evidence of the effectiveness of immunosuppressive therapy in patients with immunoglobulin (Ig A) nephropathy.

Key points

1. 1 Patients with isolated hematuria under 50 years of age should be referred to a nephrologist.
2. 2 Patients over 50 years of age are initially referred to a urologist to exclude pathologies of the bladder and prostate.
3. 3 Even a slight increase in plasma creatinine indicates significant impairment of renal function.
4. 4 Alcohol-induced liver damage is not accompanied by severe symptoms.