How to get tested for daily protein loss. Daily proteinuria. Preparing for a 24-hour urine test

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Proteinuria is the excretion of protein(s) in the urine. An increase in the level of total protein in the urine is a common finding when examining adults, children and pregnant women.

The functions of the doctor when identifying it include assessing the severity of proteinuria, differential diagnosis between benign conditions and severe pathology, and determining the tactics for managing such a patient.

In this article we will look at what physiological and pathological proteinuria is, for what reasons it occurs, and also talk about how to correctly take a urine test for daily proteinuria.

A patient’s question about proteinuria usually arises after visiting a doctor and performing a general urine test. The doctor may say: “You have an increased level of protein in your urine. You need to retake the urine test...”

After these words, the patient may begin to panic, but there is no need to pointlessly rush to the computer and search the Internet for recipes for improving health at home, brewing herbs and drinking urological preparations.

Let's figure out when proteinuria occurs and when it requires close attention from a nephrologist.

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1. Introduction to terminology
In a healthy person, the total excretion of proteins in urine normally does not exceed 100 mg/day (200 mg/l according to B.M. Brenner, 2007; B. Haraldsson et al., 2008, ). This situation is called physiological proteinuria.
In this case, in a general urine test, the patient’s protein content does not exceed 0.033 g/l (laboratory technicians write “neg.” or traces, sometimes they indicate the amount in grams/liter).
Pathological proteinuria is the excretion of more than 150 mg/day of protein in the urine (more than 0.033 g/l according to a general urine test). Daily urinary protein excretion in healthy individuals can sometimes reach or exceed the physiological level of proteinuria under certain circumstances.
Proteinuria in a general urine test is detected in 1-2 people out of 10 in the population, of which 2% have severe diseases that can be treated.
Proteinuria may conditionally be “benign”, or may indicate serious illness. The doctor’s task is to differentiate the causes of increased protein levels in the urine.
Benign pathological processes that provoke the appearance of protein in the urine:
1. 1 Fever,
2. 3 Emotional stress,
3. 4 Acute diseases not accompanied by damage to the renal tissue.
Serious diseases include:
1. 1 Glomerulonephritis;
2. 2 Multiple myeloma;
3. 3 Nephropathies.
If it is necessary to quantify proteinuria, the doctor may prescribe a 24-hour urine collection followed by an assessment of the amount of protein.
Calculating the protein/creatinine ratio in a random portion of urine is more informative and convenient than performing an analysis for daily proteinuria.

The most common causes of increased protein levels in the urine:
1. 1 Dehydration;
2. 2 Emotional stress;
3. 3 Overheating;
4. 4 Inflammatory process;
5. 5 Hard physical labor;
6. 6 Most acute diseases;
7. 7 Urinary tract infections;
8. 8 Preeclampsia and preeclampsia in pregnant women;
9. 9 Orthostatic disorders.
Approximately 20 percent of the protein excreted in urine is low molecular weight protein (for example, immunoglobulins with a molecular weight of 20,000 Da), 40 percent is high molecular weight albumin (molecular weight 65,000 Da), and 40 percent is Tamm-Horsfall mucoprotein (uromodelin), a protein which is secreted by the cells of the distal tubules and the ascending loop of Henle.

2. Mechanisms of proteinuria
Protein filtration begins in the glomeruli. The glomerular capillaries are easily permeable to fluid and small particles, but are a barrier to plasma proteins.
The basement membrane adjacent to the capillaries and the epithelial lining are coated with heparan sulfate, which gives the barrier a negative charge.
Proteins with low mass (20,000 Da) easily pass the capillary barrier. Albumin (mass 65,000 Da) has a negative charge (repels from the negatively charged glomerular basement membrane); normally, only a small amount of albumin can pass through the capillary barrier.
Proteins that are filtered into the primary urine are reabsorbed in the proximal tubules, and only a small part is excreted in the urine.
The pathophysiological mechanisms of proteinuria can be classified as glomerular, tubular and overload mechanisms.
Table 1 - Classification of proteinuria
Among the 3 pathophysiological mechanisms (glomerular, tubular, overload) that lead to the development of proteinuria, the glomerular mechanism is the most common pathology.
Figure 1 - Main causes of pathological proteinuria. Source - Consilium Medicum
Diseases of the glomeruli lead to disruption of the permeability of their basement membrane, leading to the loss of albumin and immunoglobulins in the urine.
Dysfunction of the glomeruli leads to severe protein losses, loss in urine of 2 or more grams of protein per day.

Tubular proteinuria develops as a result of impaired reabsorption of low molecular weight proteins in the proximal tubules against the background of tubulointerstitial kidney diseases.
In the presence of tubulointerstitial pathology, less than 2 grams of protein is usually excreted in urine per day.

Tubular pathology develops with hypertensive nephrosclerosis, tubulointerstitial nephropathy caused by taking NSAIDs.
With proteinuria overload, the amount of low molecular weight protein entering the primary urine after glomerular filtration is so large that it exceeds the ability of the kidneys to reabsorb it.

Most often, overload proteinuria is the result of excessive formation of immunoglobulins in the body (more common in multiple myeloma). In case of multiple myeloma, Bence Jones protein (immunoglobulin light chains) is detected in the urine.
Table 2 - The main causes of protein loss according to the results of the analysis for daily proteinuria

3. Calculation of protein loss in urine
Calculation of urinary protein loss can be done using the following laboratory tests:
1. 1 General urine test.
2. 2 Use of test strips (express methods).
3. 3 Test with sulfosalicylic acid.
4. 4 Determination of daily proteinuria (distorted, urine analysis for daily protein).
5. 5 Determination of the protein/creatinine ratio in a random portion of a urine test is an alternative to testing for daily proteinuria.
Studies have shown that the protein/creatinine ratio is more accurate than the 24-hour proteinuria test.

A protein/creatinine ratio of less than 0.2 corresponds to the release of 0.2 grams of protein per day and is normal; a ratio of 3.5 corresponds to daily proteinuria of 3.5 grams of protein per day.

4. Preparation for analysis for daily proteinuria
1. 1 No special training required.
2. 2 The day before taking the test for daily protein in the urine, it is necessary to avoid taking diuretic medications, avoid stress, heavy physical activity, and avoid drinking alcohol and ascorbic acid (Vit. C).
5. How to take a urine test correctly?
1. 1 The first morning urine sample is not tested for 24-hour proteinuria; the patient urinates in the toilet.
2. 2 Subsequently, all urine is collected into a pre-purchased container (sold in paid laboratories and pharmacies), including the first morning portion for the next day.
3. 3 In addition to protein, the study must include a urine test for creatinine to assess the adequacy of the analysis. The amount of creatinine released is proportional to muscle mass and is constant. Men excrete on average 16-26 mg/kg of creatinine per day, women – 12-24 mg/kg/day.
4. 4 The last urination is carried out exactly one day after the first.
5. 5 The urine collected in one container is mixed, the total volume of urine is recorded. 30-50 ml of urine is poured into a separate sterile container.
6. 6 On the container you must make a note about the daily volume of urine, indicate your height and weight.
7. 7 Store urine collection containers at temperatures from +2 to +8C.
6. Protein in urine during pregnancy
During pregnancy, the volume of circulating blood increases, the volume of blood flow in the kidneys increases, and, consequently, the glomerular filtration rate increases. This leads to a physiological decrease in plasma creatinine concentration.
The amount of protein in the urine increases as a result of an increase in the glomerular filtration rate and an increase in the permeability of glomerular membranes, a decrease in the reabsorption of proteins in the proximal tubules.
In a general urine test during pregnancy, an increase in protein content to 0.066 g/l is considered acceptable. The standard test for daily proteinuria in pregnant women is up to 300 mg/day.
Proteinuria in pregnant women above 300 mg/day (more than 0.066 g/l according to general urine analysis) is considered pathological. It is important to remember that proteinuria during pregnancy is usually a symptom of gestosis and preeclampsia.
The combination of proteinuria, bacteriuria and leukocyturia during pregnancy indicates urinary tract infections. Other causes of pathological proteinuria can be seen in Table 3 below.
Table 3 - Differential diagnosis of proteinuria during pregnancy. Source - Consilium Medicum
In conclusion, let us once again emphasize the main points:
1. 1 There are three mechanisms for the development of proteinuria - glomerular, tubular, overload.
2. 2 Currently, an alternative to analyzing daily proteinuria is calculating the protein/creatinine ratio (easier to perform, more accurate results).
3. 3 Not all collected urine is taken for analysis, but only 30 ml of the total volume after mixing.

Daily proteinuria is an indicator of the general condition of the body and the functional activity of the kidneys. It can act as the first sign of a developing disease of internal organs, the presence of a focus of chronic infection in the tissues of the genitourinary system.

general characteristics

Daily protein in urine reaches its maximum level during the day, when a person leads an active life, walks a lot, and is in an upright position.

In humans, daily protein loss may be associated with the negative effects on the body of the following factors:

psycho-emotional stress, being in a stressful situation when the nervous system is in an excited state for a long period of time;
fever, chills, overheating of the body due to exposure to high temperatures (a similar reaction of the kidneys is observed in people with ARVI, when an acute immune reaction occurs, and the patient’s fever remains at 38-39 degrees Celsius);
hiking over long distances (loss of protein along with urination is caused by prolonged static load on the feet, which negatively affects the glomerular filtration of the kidneys);
heavy physical activity, lifting weights, intense sports, squats with heavy weights;
stagnation of fluid in the lower extremities and internal organs, if a person has a concomitant disease in the form of heart failure (in this case, the excretion of protein along with urine continues until sufficient activity of the heart rhythm is restored);
hypothermia of the body, prolonged exposure to conditions of extremely low atmospheric temperatures (brain centers reduce energy consumption by internal organs to a minimum, the kidneys work almost exclusively on urination, filtration is insignificant, which causes the release of not only protein, but also other unfiltered cells and particles);
inflammatory diseases of the kidney tissue resulting from bacterial infection of the organ or hypothermia of the lumbar back;
intoxication of the body due to exposure to harmful chemicals, when the kidneys cannot functionally cope with a large volume of toxic elements that require filtration and excretion along with urine;
long-term use of medications, the side effects of some of them are to create additional stress on the functioning of the organs of the excretory system;
other kidney diseases that impair the functions of the glomerular filter.

It is important to remember that daily proteinuria is divided into two main types depending on what type of protein compounds are excreted in large quantities over the last 24 hours. The release of negatively charged proteins leads to the development of selective proteinuria, which is the most common and most often encountered in practical urology.

The loss of low molecular weight positively charged proteins is daily albuminuria, which indicates that a person has serious heart disease, intoxication of the body, or infection with a dangerous infection.

Excretion of protein in urine is possible only in small quantities. Most of the proteins that overcome the filtration barrier of the kidneys (at least 98%) are absorbed back into the cavities of the proximal tubules.

Classification

The results of protein concentration in urine collected over the last 24 hours are divided according to the severity and filtration activity of the kidneys.

Based on these data, a conclusion is made about the possible presence of a specific disease of the internal organs, namely:

150-500 mg of protein in the urine is a mild type of proteinuria, which develops under the influence of diseases such as acute hematuric glomerulonephritis, hereditary nephritis, uropathy caused by obstructive processes in the kidney tubules;
500-2000 mg of protein in urine is a moderately expressed proteinuria, when with a high degree of probability the patient develops chronic glomerulonephritis, nephritis caused by streptococcal infection or arising against the background of a genetic predisposition of the body (especially common in adults and children in whose family there is blood relatives suffering from a similar disease);
over 2000 mg of protein in daily urine is a clear sign of the development of acute nephrotic syndrome or amyloidosis (the patient needs urgent hospitalization and drug therapy aimed at maintaining the functioning of the excretory system so that chronic renal failure does not occur, its presence always leads to disability and dependence person from hemodialysis).

The main task of the attending physician, diagnosing and interpreting the analysis for daily proteinuria, is to promptly detect an increase in protein in the patient’s urine and prevent the pathology from moving to the next stage with an increase in the concentration of protein in urine.

Normal indicators

To determine the concentration of protein in the body over the last 24 hours, a 24-hour urine test for protein is performed. If its level exceeds the permissible norms, the patient is prescribed a repeat test to confirm or refute the diagnosis.

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A daily urine test for protein has the same standards for the optimal protein concentration in both men and women. The method of laboratory testing of urine is called colorimetry. The generally accepted unit of measurement for sampled biological material is milligrams of detected proteins in urine collected over the past 24 hours.

The concentration of protein compounds is calculated using a special formula, which includes initial data in the form of the total volume of the selected biological fluid and its density.

The amount of protein in daily urine should not exceed 140 mg. Anything above this level indicates the first signs of a systemic disease that reduces the filtration activity of the kidneys. The only exceptions are the results obtained for patients whose bodies have experienced intense physical activity or a stressful situation. In this case, a urine test for daily proteinuria may have a norm of 250 mg of detected proteins.

Urine collection rules

How to properly collect daily urine? To ensure that the results of biochemical analysis of urine are not distorted by the influence of various environmental factors, the following rules for collecting daily urine must be observed:

the first trip to the toilet, when it is planned to collect a daily urine sample, should be done in the toilet (it is believed that after a night too much urine containing the end products of metabolic processes accumulates in the bladder);
all subsequent urinations for analysis of daily proteinuria are performed in a pre-prepared container, it must be sterile, purchased at a pharmacy or obtained in a laboratory (the recommended volume of the container must be at least 2 liters to accommodate all the biological fluid secreted during the day) ;
storage of daily urine output is carried out in a dark and cool place so that access to direct sunlight is excluded (so that the analysis of daily urine is not affected by temperature disturbances, it is recommended to place the container in the refrigerator, having previously removed products with hygroscopic properties - butter, honey, margarine, confectionery products, milk);
on the day of taking a urine test for proteinuria, do not plan long trips, limit the consumption of excess amounts of protein, fatty and salty foods, avoid hypothermia, physical exertion, and psycho-emotional stress;
after 24 hours from the start of the daily proteinuria analysis, you should remove the container with the collected urine from the refrigerator, record the total volume of the excreted liquid, and then mix it thoroughly by shaking;
take a sterile plastic jar and pour 50 ml of daily urine from the container, which reflects the general clinical picture of kidney functionality, how pronounced the total protein excretion is over the last 24 hours;
As soon as possible, submit your urine to the laboratory where the analysis will be carried out.

It is difficult to determine daily proteinuria at home; you will need to take at least a test. Based on its results, one can not only judge the presence or absence of a symptom, but also make assumptions regarding concomitant pathologies, as well as determine a set of diagnostic and therapeutic measures. However, it may be a functional phenomenon and does not require treatment.

The formation of proteinuria in the human body

In the process of performing its main task, a small amount of protein is filtered from the bloodstream. This is how it appears in primary urine.

Next, the mechanism of protein reabsorption in the renal tubules is triggered. The result of the functioning of healthy kidneys and the absence of excess proteins in the blood plasma is the presence of a small amount of protein in secondary urine (the fluid that is excreted from the body).

A laboratory test of urine does not detect proteins at this concentration, or gives a result of 0.033 g/l.

Exceeding this value is called proteinuria - the content of protein in urine in large quantities. This condition is a reason for further diagnosis in order to identify the causes of the disorder.

Types of proteinuria - physiological and pathological forms

Depending on the source of protein in urine, the following types of disorders can be distinguished:

Renal(renal) - in which excess protein is formed due to defects in glomerular filtration (glomerular or glomerular proteinuria), or when reabsorption in the tubules is impaired (tubular or tubular).
Prerenal– occurs when there is an inadequately high formation of protein compounds in the blood plasma. Healthy kidney tubules are not able to absorb such amounts of protein. It can also occur with artificial administration of albumin against the background.
Postrenal– caused by inflammation of the organs of the lower genitourinary system. The protein enters the urine that comes out of the kidney filter (hence the name - literally “after the kidneys”).
Secretory– characterized by the release of a number of specific proteins and antigens against the background of certain diseases.

All of the listed mechanisms of protein getting into the urine are characteristic of a pathological process occurring in the body, therefore such proteinuria is called pathological.

Functional proteinuria is most often an episodic phenomenon, not accompanied by diseases of the kidneys or genitourinary system. These include the following forms of violation:

Orthostatic(lordotic, postural) - the appearance of protein in the urine in children, adolescents or young people of asthenic physique (often against the background of lumbar lordosis) after prolonged walking or being in a static upright position.
Nutritional– after eating protein foods.
Proteinuria tension(working, marching) – occurs under conditions of extensive physical activity (for example, among athletes or military personnel).
Feverish– occurs as a result of increased decay processes in the body or damage to the kidney filter when body temperature rises above 38 degrees.
Palpation– may appear against the background of prolonged and intense palpation of the abdominal area.
Emotional– diagnosed during times of severe stress or as a consequence of it. This can include the transient form, also associated with shock changes in the body due to hypothermia or heat stroke.
Stagnant- a phenomenon that accompanies abnormally slow blood flow in the kidneys or oxygen starvation of the body in heart failure.
Centrogenic– occurs with concussions or epilepsy.

The appearance of proteins in the urine in functional forms can be explained by mechanisms similar to pathological forms. The only difference is the transitory nature and quantitative indicators.

It is worth noting that the last two functional forms are often combined under the name of extrarenal proteinuria, which is also included in the list of pathological forms.

Norms of daily proteinuria

Based on the abundance of only the main types of functional forms, it can be assumed that a one-time excess of the amount of protein in the urine is not always necessary and is clearly not sufficient to identify a stable trend. Therefore, it is more correct to use the results of the analysis.

If there are a number of physiological reasons, the daily norm can also be exceeded in healthy people; to make a diagnosis, it is necessary to take into account the patient’s complaints, as well as other quantitative indicators of urine analysis (red blood cells,).

The general daily protein requirement for adults is 0.15 g/day, and according to other reference data - 0.2 g/day (200 mg/day) or a lower value - 0.1 g/day.

These figures, however, are only valid for 10-15% of the population; the vast majority excrete only 40-50 mg of protein in urine.

During pregnancy, the volume of blood flow in the kidneys increases, and the amount of filtered blood increases accordingly. This is taken into account when calculating protein norms. Non-pathological indicator in pregnant women is less than 0.3 g/day (150-300 mg/day).

Norms for children can be presented in table form:

Some deviation from the norm (increasingly) can be observed in children in the first week of life.

For any type of functional proteinuria, the quantitative indicator rarely exceeds 2 g/day, and more often – 1 g/day. Similar values can be observed in some pathologies; here it is important to conduct additional research and examination of the patient. The exception is pregnant women, whose daily value is more than 0.3 g/day, which already makes it possible to suspect the presence of pregnancy complications with a high probability.

Causes of protein in urine

It is convenient to consider the general list of diseases, a sign of which is the presence of protein in the urine, in accordance with the pathological forms. The prerenal form of proteinuria can occur against the background of:

some types of systemic and regional hemoblastoses - malignant changes in hematopoietic and lymphatic tissue (including multiple myeloma);
connective tissue diseases - disorders of an allergic nature, in which various (from 2) body systems are affected;
rhabdomyolysis - a condition characterized by the destruction of muscle tissue and a sharp increase in the concentration of myoglobin protein in the blood;
macroglobulinemia - a disease in which malignantly modified plasma cells begin to secrete a viscous protein - macroglobulin;
hemolytic anemia – accompanied by the breakdown of red blood cells and the release of a large amount of hemoglobin protein into the blood (may occur due to poisoning with specific poisons);
transfusion of incompatible blood or taking medications (sulfonamides);
the presence in the body of metastases or tumors localized in the abdominal cavity;
poisoning;
epileptic seizure or traumatic brain injury, including those accompanied by cerebral hemorrhage.

The causes of the renal form are directly renal pathologies:

– characterized by damage to the glomerular apparatus of the kidneys, and in some cases, death of tubular tissue;
– impaired renal function that occurs against the background of changes in the metabolism of fats and carbohydrates with high blood pressure;
hypertensive – “wrinkling” of the kidney tissue as a result of vascular damage due to high blood pressure;
renal neoplasms;
– deposition of protein complexes – amyloids – in the kidneys;
inflammatory kidney diseases, in particular interstitial nephritis - inflammation of the connective tissue of the tubules.

Postrenal proteinuria may be a symptom of:

inflammatory diseases of the lower part of the genitourinary system - bladder, urethra, genitals;
bleeding from the urethra;
benign neoplasms of the bladder () and urinary tract.

In all of these (postrenal) cases, the epithelial cells of the mucous membrane are damaged. Their destruction releases proteins, which are found in urine.

Proteinuria in children can also develop due to a number of the listed reasons. In this case, the occurrence of excess protein against the background of:

hemolytic disease of newborns is a type of hemoblastosis, the specificity of which is the incompatibility of the blood of the mother and the fetus. Pathology can begin to develop even in the intrauterine period of the embryo’s life;
fasting or eating disorder;
excess vitamin D;
allergies.

An increase in the amount of protein in urine during pregnancy may also have a number of additional reasons:

nephropathy of pregnancy;
toxicosis (in the first trimester) - a violation of the water-salt balance against the background of dehydration, leading to a change in general metabolism;
gestosis (preeclampsia) is a complicated pregnancy, accompanied by hypertension, cramps, edema, proteinuria. The condition is usually diagnosed in the 2nd and 3rd trimester.

Symptoms accompanying this disease

Common signs that urinary protein loss is occurring include:

edematous manifestations, in particular morning swelling of the eyelids;
the appearance of whitish foam or dirty white flakes on the surface of urine.

Differentiated signs may include both symptoms of loss of a certain type of protein compounds, and symptoms of the underlying cause of proteinuria. Among the first:

general decrease in immunity;
anemic manifestations;
tendency to bleed;
weakness, decreased muscle tone;
hypothyroidism

The second includes mainly signs indicating the presence of renal pathologies:

pain in the kidneys, including;
discomfort when urinating;
increased blood pressure;
high fever, chills, muscle pain;
weakness, dry skin;
change in the color, consistency or smell of urine;
diuresis disorders.

However, the main source of information for making a diagnosis and determining the cause of excess protein is laboratory tests.

Method of diagnosing the disease

After a one-time detection of proteinuria as a result of a general urinalysis, functional and pathological forms should be differentiated. This may require:

collecting patient complaints, determining the presence of factors that can provoke an episodic increase in protein levels;
orthostatic test - performed in children and adolescents.

If there is a suspicion of concomitant pathology, then the following are prescribed:

daily protein analysis;
tests for specific proteins (Bence-Jones);
examination by a urologist or gynecologist;
, genital organs (if indicated).

general and biochemical blood tests.

Naturally, the complex of additional examinations can expand significantly, according to the fact that a variety of diseases can cause proteinuria, acting as a primary/secondary cause of increased protein levels.

How to prepare for the test

No special measures are required, but some nuances are worth considering:

You must notify your doctor about taking any medications on an ongoing basis and, if necessary, agree with him on the advisability of their use on the day of the test;
do not change the drinking regime, both before and during it;
do not eat unusual foods, follow your usual diet;
exclude alcoholic drinks;
the day before the test, you should stop taking vitamin C;
avoid physical and nervous overload;
If possible, provide the body with adequate sleep.

How to take a daily protein test correctly

To obtain an adequate analysis result, the patient will need to follow the following algorithm:

Prepare (purchase) in advance for collecting the daily volume of urine.
There is no need to collect the first portion of morning urine.
Now, with each urination, urine should be added to the container, recording the time of each diuresis. Store the collected volume only in the refrigerator.
You need to collect all urine, including the first morning portion the day after the start of collection (to get urine output for the day).
After completing the collection, record the resulting volume of liquid;
Mix the urine and pour from 30 to 200 ml into a separate sterile container.
Submit the container to the laboratory, adding a recorded graph of diuresis, as well as indicating the final volume of fluid received, your height and weight.

Minor proteinuria can be corrected at home using the following measures:

minimizing physical and emotional stress;
making changes to the diet - consume less heavy proteins (fatty meat and fish, mushrooms, legumes) and salt, while increasing the amount of fiber - steamed vegetables, fruits, cereals, bread and dairy products, dairy and vegetable soups.

A diet with a high protein content also involves avoiding alcoholic beverages and cooking food with a small amount of fat - boiling or steaming.

There are many known folk remedies that help reduce the amount of protein in the urine, here are some of them:

infusions of seeds or roots of parsley, birch buds, bearberry;
(grains, not flakes), corn grains or fir bark;
decoction of pumpkin seeds instead of tea;
teas and;
infusions of linden and lemon zest.

Recipes for decoctions of herbs, tree bark and grains for drinking:

Brew a teaspoon of chopped parsley seeds with boiling water and leave for several hours. Take several sips throughout the day.
Pour boiling water over two tablespoons of birch buds and leave for 1-2 hours. Take 50 ml 3 times a day.
Boil 4 tablespoons of corn kernels in water (about 0.5 liters) until softened. Then strain and drink throughout the day. The decoction should not be stored for longer than a day.
Boil 5 tablespoons of oat grains in a liter of water until softened; take the decoction in the same way as corn decoction.

During pregnancy, the diet does not lose its relevance, as does the use of folk remedies. But taking chemical medications should be strictly as prescribed by the doctor (although this recommendation should not be neglected even in the absence of pregnancy).

It is important to understand that at home you can only fight a functional disorder or one that is just beginning to develop. In case of massive deviations from the norm as a result of urine analysis and severe symptoms, the listed measures can act as an addition to the main drug therapy.

But the latter can be represented by drugs of various groups:

latest generation statins - for the treatment of diabetes mellitus and vascular atherosclerosis (some statins, however, may themselves contribute to proteinuria);
ACE inhibitors and angiotensin blockers - used for heart pathologies, in particular arterial hypertension;
calcium channel blockers - often used to treat the combination of hypertension and diabetes mellitus;
antitumor drugs – used in the presence of benign or malignant neoplasms;
antibiotics and – are prescribed in the presence of an inflammatory process and/or the presence of infections;
anticoagulants – have a complex effect in acute glomerulonephritis and renal failure;
non-hormonal immunosuppressants (cytostatics) – suppress the inflammatory autoimmune process in glomerulonephritis or nephrotic syndrome against the background of high blood pressure;
complex or narrowly targeted means to reduce swelling;
hormonal drugs (corticosteroids) - have an antiallergic and anti-inflammatory effect, but can increase blood pressure.

Treatment of severe proteinuria, which is also complicated by a serious illness, can require effort and significant time. Therefore, even with the occasional appearance of protein in the urine, one should not neglect the diagnosis and use of “home” therapeutic measures in order to prevent the development of pathologies of the kidneys and the body as a whole.

The composition of urine determines many processes, including human health. Every day, organic substances and electrolytes enter the urine in varying quantities. Every day the body releases up to 70 milligrams of substances in the urine. The composition of the fluid secreted by the body is constantly changing, even in people who do not suffer from kidney inflammation.

The patient is often asked to collect a daily allowance for testing presence of protein in urine if the doctor suspects he has proteinuria.

Why check for protein in urine?

In a person who does not complain about his health, urine has a composition with indicators close to normal. If a malfunction occurs in the body, this is often indicated by the presence protein in urine.

During normal functioning of internal organs, protein is filtered by the kidneys and should not enter the urine.

Modern urine tests make it possible to make a diagnosis in the shortest possible time. A daily protein analysis allows you to determine the amount of urine excreted in one day, and presence of sugar and protein. Based on the indicators obtained as a result of the analysis, the doctor can make a diagnosis.

Is increased protein in urine dangerous? Read our article.

The doctor suggests taking a daily test for the presence of protein after protein is detected in the general urine test. In addition, the analysis may be prescribed due to a high risk of developing:

renal failure;
various diseases associated with connective tissues;
diabetes mellitus;
coronary heart disease;
nephropathy.

If your urine contains too little protein, this is not a cause for concern, as many doctors consider this to be normal.

This may occur as a result of insufficient consumption of protein-based foods or exhausting sports training.

The presence of protein in urine indicates not only about nephrotic syndrome, but also about the possible development of autoimmune diseases. Sometimes excess protein indicates the presence of poisons in the human body or severe drug overdose

Experts divide them into different types and diagnose the disease based on this. Albumin is considered a common type of protein. It is he who points to kidney inflammation and cardiovascular diseases.

Types of daily urine analysis

Testing through urine analysis is carried out to identify substances of various nature. When submitting urine, the following is checked within 24 hours:

squirrel. The daily excretion of this substance should not exceed one hundred fifty milligrams per day;
leukocytes and cylinders. It is the cellular component of urine. Normal levels of leukocytes are no more than two million, cylinders with daily collection - should not exceed twenty thousand;
glucose. This parameter should be taken into account when monitoring the effectiveness of therapy against diabetes mellitus. Basically, the level of glucose in the urine increases with hormonal diseases. The level is said to be exceeded if it is detected in the urine more than 1.6 millimoles glucose per day;
oxalates. These are salts from oxalic acid. Their increased content is typical for endocrine, intestinal, hepatic, and renal disorders;
creatinine. This is a special type of daily analysis, the so-called Rehberg test.

Range from 5.3 to 17 millimoles per day characteristic of the normal state. This parameter characterizes cardiovascular, endocrine and renal diseases.

How to assemble correctly?

Before you begin taking the daily test, you need to complete training one day before the expected collection procedure.

It is necessary to completely exclude spicy foods and foods with a high salt content while preparing for delivery. Sweet flour products should also not be eaten; fast food products should be avoided.

One of the main rules before starting urine collection is exclusion of alcoholic beverages. Juices saturated with processed vegetables will spoil the indicator, so you should not drink them.

If a person took diuretics and herbs, then you also need to temporarily abandon them. Donating urine during the menstrual cycle is also contraindicated.

Liquid can be collected in a purchased container volume of at least 2.8 liters or in a three-liter jar. One of the important conditions is the cleanliness of the container and a dry bottom.

After the first trip to the toilet, you do not need to collect urine, but you should note on a special sheet what time the urination process took place. Subsequent releases of liquid are carried out into one jar. This procedure is performed for one day.

The last urine collection for analysis is carried out exactly one day after the mark placed on a special sheet.

Before each analysis is carried out hygiene care behind the genitals. To ensure the accuracy of the analysis, experts recommend that women cover the vagina with a special tampon in order to prevent microflora isolated from the vagina from entering the collection container.

After each trip to the toilet, the container is placed in a dark place, which should be at a low temperature. The ideal place to store urine is fridge. The jar is placed on the bottom or other shelf away from common products.

After all fees have been completed, you need to note the amount of urine collected in one day, this indicator will be daily diuresis, which is measured in milliliters.

How is the procedure for collecting protein loss per day carried out?

When determining daily loss of protein in urine identify the state of the kidneys and glomerular apparatus. This method is quite informative and has gained popularity due to the ease of urine collection.

This study aims to detection of kidney pathology. During the inflammatory process occurring in the kidneys, the membrane becomes inflamed and protein molecules penetrate through it. The amount of proteins identified during the study indicates the degree of damage to the glomerular apparatus.

In order for a doctor to decide to prescribe such an analysis, serious reasons are needed, such as:

diagnosis of various autoimmune inflammations occurring in the kidneys, which are accompanied by the release of protein;
the presence of malignant tumors found in the kidneys, with further determination of localization in other organs;
detection of an inflammatory process in the renal system, which is called pyelonephritis;
Zimnitsky study, prescribed for prevention purposes.

Another reason for conducting such a study is inability to make a diagnosis based on the procedures performed.

In order for the urine collection process to proceed correctly, you need to follow the step-by-step steps:

One day before the expected urine collection, you should not consume beets, carrots and alcoholic beverages.
Urine collection begins in the morning, usually at six o'clock.
During the day, you need to collect in the same container, which should hold at least three liters.
The collection is completed at the same time the next day. If the first collection was made at six in the morning, then the final urine should be sent to the container at six in the morning of the next day.
After completing urine collection, you need to measure its total fullness.
Part of the collected liquid in an amount of about two hundred milliliters is poured into a separate container.
The last step is to send the container to the laboratory for testing.

Before collecting fluid for analysis, you must completely avoid taking antibiotics and radiocontrast agents.

The presence of these substances in a patient’s analysis can lead to a false-positive result. If such a mistake was made, the doctor may suggest a new urine collection.

What is daily proteinuria?

Protein, or protein as it is also called, is the basis for muscle, spine and nerve cells in the body. Proteins are divided into two types: albumins and globulins. Globulins have a large molecular weight and have low solubility. Albins are smaller in mass and are better able to dissolve.

The kidney glomeruli normally prevent the passage of large molecules, so only albumin and low molecular weight immunoglobulins can be found in the urine of a healthy person.

The listed proteins are characterized by so-called “protein traces”, or in quantitative ratio no more than 140 mg/ml urine.

Proteinuria can cause natural and pathological factors. The first include hypothermia, emotional and mental stress, sports, improper diets, and pregnancy.

Pathological protein loss occurs mainly due to renal causes. In rare cases, this is an extrarenal pathology associated with an infection in which protein enters the urine without passing through the kidneys.

Find out how to take a general urine test from the video:

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Small amounts of protein are found in 24-hour urine in healthy individuals. However, such small concentrations cannot be detected using conventional research methods. The release of greater amounts of protein, at which the usual qualitative tests for protein in the urine become positive, is called proteinuria. There are renal (true) and extrarenal (false) proteinuria. With renal proteinuria, protein enters the urine directly from the blood due to increased filtration by the glomeruli of the kidney or decreased tubular reabsorption.

Renal (true) proteinuria

Renal (true) proteinuria can be functional or organic. Among functional renal proteinuria, the following types are most often observed:

Physiological proteinuria of newborns, which disappears on the 4th to 10th day after birth, and in premature infants somewhat later;
- orthostatic albuminuria, which is typical for children aged 7-18 years and appears only in an upright position of the body;
- transient (stroke) albuminuria, the cause of which can be various diseases of the digestive system, severe anemia, burns, injuries or physiological factors: heavy physical activity, hypothermia, strong emotions, plentiful, protein-rich foods, etc.

Organic (renal) proteinuria is observed due to the passage of protein from the blood through damaged areas of the endothelium of the renal glomeruli in kidney diseases (glomerulonephritis, nephrosis, nephrosclerosis, amyloidosis, nephropathy of pregnant women), disorders of renal hemodynamics (renal venous hypertension, hypoxia), trophic and toxic (including including medicinal) effects on the walls of glomerular capillaries.

Extrarenal (false) proteinuria

Extrarenal (false) proteinuria, in which the source of protein in the urine is an admixture of leukocytes, erythrocytes, bacteria, and urothelial cells. observed in urological diseases (urolithiasis, kidney tuberculosis, kidney and urinary tract tumors, etc.).

Determination of protein in urine

Most qualitative and quantitative methods for determining protein in urine are based on its coagulation in the volume of urine or at the interface of media (urine and acid).

Among the qualitative methods for determining bek in urine, the most widely used are the unified test with sulfosalicylic acid and the Heller ring test.

A standardized test with sulfasalicylic acid is carried out as follows. 3 ml of filtered urine is poured into 2 test tubes. 6-8 drops of a 20% solution of sulfasalicylic acid are added to one of them. Both test tubes are compared against a dark background. Cloudy urine in a test tube containing sulfasalicylic acid indicates the presence of protein. Before the study, it is necessary to determine the urine reaction, and if it is alkaline, then acidify it with 2-3 drops of a 10% acetic acid solution.

The Heller test is based on the fact that in the presence of protein in the urine, coagulation occurs at the border of nitric acid and urine and a white ring appears. 1-2 ml of a 30% nitric acid solution is poured into a test tube and exactly the same amount of filtered urine is carefully layered along the wall of the test tube. The appearance of a white ring at the border of two liquids indicates the presence of protein in the urine. It should be remembered that sometimes a white ring is formed in the presence of a large amount of urates, but unlike the protein ring, it appears slightly above the boundary between two liquids and dissolves when heated [Pletneva N.G., 1987].

The most commonly used quantitative methods are:

1) the unified Brandberg-Roberts-Stolnikov method, which is based on the Heller ring test;
2) photoelectrocolorimetric method for the quantitative determination of protein in urine by the turbidity formed by the addition of sulfasalicylic acid;
3) biuret method.

Detection of protein in urine using a simplified, accelerated method is carried out using a colorimetric method using indicator paper produced by Lachema (Slovakia), Albuphan, Ames (England), Albustix, Boehringer (Germany), Comburtest etc. The method consists of immersing a special paper strip soaked in tetrabromophenol blue and citrate buffer in urine, which changes its color from yellow to blue depending on the protein content in the urine. The approximate concentration of protein in the test urine is determined using a standard scale. To obtain correct results, the following conditions must be met. Urine pH should be in the range of 3.0-3.5; urine that is too alkaline (pH 6.5) will result in a false positive, and urine that is too acidic (pH 3.0) will result in a false negative.

The paper should be in contact with the urine being tested for no longer than indicated in the instructions, otherwise the test will give a false positive reaction. The latter is also observed when there is a large amount of mucus in the urine. The sensitivity of different types and batches of paper may vary, so the quantification of protein in urine by this method should be treated with caution. Determining its amount in daily urine using indicator paper is impossible [Pletneva N.G., 1987]

Determination of daily proteinuria

There are several ways to determine the amount of protein excreted in urine per day. The simplest is the Brandberg-Roberts-Stolnikov method.

Methodology. 5-10 ml of thoroughly mixed daily urine is poured into a test tube and a 30% nitric acid solution is carefully added along its walls. If there is protein in the urine in an amount of 0.033% (i.e. 33 mg per 1 liter of urine), a thin but clearly visible white ring appears after 2-3 minutes. At a lower concentration, the sample is negative. If there is a higher protein content in the urine, its amount is determined by repeated dilutions of the urine with distilled water until a ring ceases to form. In the last test tube, in which the ring is still visible, the protein concentration will be 0.033%. By multiplying 0.033 by the degree of urine dilution, the protein content in 1 liter of undiluted urine is determined in grams. Then the protein content in daily urine is calculated using the formula:

K=(x V)/1000

Where K is the amount of protein in daily urine (g); x - amount of protein in 1 liter of urine (g); V is the amount of urine excreted per day (ml).

Normally, during the day, from 27 to 150 mg (on average 40-80 mg) of protein is excreted in the urine.

This test allows you to determine only finely dispersed proteins (albumin) in urine. More accurate quantitative methods (Kjeldahl's colorimetric method, etc.) are quite complex and require special equipment.

With renal proteinuria, not only albumin, but also other types of protein are excreted in the urine. A normal proteinogram (according to Seitz et al., 1953) has the following percentage: albumin - 20%, α 1 -globulins - 12%, α 2 -globulins - 17%, γ-globulins - 43% and β-globulins - 8% . The ratio of albumins to globulins changes in various kidney diseases, i.e. the quantitative relationship between protein fractions is disrupted.

The most common methods for fractionating uroproteins are the following: salting out with neutral salts, electrophoretic fractionation, immunological methods (Mancini radial immunodiffusion reaction, immunoelectrophoretic analysis, precipitation immunoelectrophoresis), chromatography, gel filtration, and ultracentrifugation.

In connection with the introduction of uroprotein fractionation methods based on the study of electrophoretic mobility, variability of molecular weight, size and shape of uroprotein molecules, it became possible to identify types of proteinuria characteristic of a particular disease and to study the clearances of individual plasma proteins. To date, over 40 plasma proteins have been identified in urine, including 31 plasma proteins in normal urine.

Selective proteinuria

In recent years, the concept of proteinuria selectivity has emerged. In 1955, Hardwicke and Squire formulated the concept of “selective” and “non-selective” proteinuria, determining that the filtration of plasma proteins into the urine follows a certain pattern: the greater the molecular weight of the protein excreted in the urine, the less its clearance and the lower its concentration in the urine. final urine. Proteinuria corresponding to this pattern is selective, in contrast to non-selective proteinuria, which is characterized by a perversion of the derived pattern.

The detection of proteins with a relatively large molecular weight in the urine indicates a lack of selectivity of the renal filter and its severe damage. In these cases, they speak of low selectivity of proteinuria. Therefore, the determination of protein fractions of urine using starch and polyacrylamide gel electrophoresis methods is now widespread. Based on the results of these research methods, one can judge the selectivity of proteinuria.

According to V.S. Makhlina (1975), the most justified is to determine the selectivity of proteinuria by comparing the clearances of 6-7 individual blood plasma proteins (albumin, traneferrin, α 2 - macroglobulin, IgA, IgG, IgM) using accurate and specific quantitative immunological methods of radial immunodiffusion reaction according to Mancini, immunoelectrophoretic analysis and precipitate immunoelectrophoresis. The degree of selectivity of proteinuria is determined by the selectivity index, which is the ratio of the compared and reference proteins (albumin).

Studying the clearances of individual plasma proteins allows us to obtain reliable information about the state of the filtration basement membranes of the glomeruli of the kidney. The connection between the nature of proteins excreted in the urine and changes in the glomerular basement membranes is so pronounced and constant that the uroproteinogram can indirectly judge pathophysiological changes in the glomeruli of the kidneys. Normally, the average pore size of the glomerular basement membrane is 2.9-4 A° NM, which can allow proteins with a molecular weight of up to 10 4 to pass through (myoglobulin, acidic α 1 - glycoprotein, light chains of immunoglobulins, Fc and Fab fragments of IgG, albumin and transferrin).

With glomerulonephritis and nephrotic syndrome, the size of the pores in the basement membranes of the glomeruli increases, and therefore the basement membrane becomes permeable to protein molecules of large size and mass (ceruloplasmin, haptoglobin, IgG, IgA, etc.). With extreme damage to the glomeruli of the kidneys, giant molecules of blood plasma proteins (α 2 -macroglobulin, IgM and β 2 -lipoprotein) appear in the urine.

By determining the protein spectrum of urine, we can conclude that certain areas of the nephron are predominantly affected. Glomerulonephritis with predominant damage to glomerular basement membranes is characterized by the presence of large and medium molecular weight proteins in the urine. Pyelonephritis with predominant damage to the basement membranes of the tubules is characterized by the absence of large-molecular proteins and the presence of increased amounts of medium- and low-molecular proteins.

β 2 -Microglobulin

In addition to well-known proteins such as albumin, immunoglobulins, lipoproteins. fibrinogen, transferrin, urine contains plasma microprotein proteins, among which β 2 -microglobulin, discovered by Berggard and Bearn in 1968, is of clinical interest. Having a low molecular weight (relative molecular weight 1800), it freely passes through the glomeruli of the kidney and almost completely reabsorbed in the proximal tubules. This allows the quantitative determination of β 2 -microglobulin in blood and urine to be used to determine glomerular filtration rate and the ability of the kidneys to resorption of proteins in the proximal tubules.

The concentration of this protein in blood plasma and urine is determined by radioimmunological method using the standard kit “Phade-bas β 2 -mikroiest” (Pharmacia, Sweden). The blood serum of healthy people contains an average of 1.7 mg/l (ranges from 0.6 to 3 mg/l), and urine contains an average of 81 μg/l (maximum 250 μg/l) of β 2 -microglobulin. Exceeding it in urine over 1000 mcg/l is a pathological phenomenon. The content of β 2 -microglobulin in the blood increases in diseases accompanied by impaired glomerular filtration, in particular in acute and chronic glomerulonephritis, polycystic kidney disease, nephrosclerosis, diabetic nephropathy, acute renal failure.

The concentration of β 2 -microglobulin in the urine increases in diseases accompanied by impaired reabsorption function of the tubules, which leads to an increase in its excretion in the urine by 10-50 times, in particular, with pyelonephritis, chronic renal failure, purulent intoxication, etc. It is characteristic that with cystitis in Unlike pyelonephritis, there is no increase in the concentration of β 2 -microglobulin in the urine, which can be used for the differential diagnosis of these diseases. However, when interpreting the results of the study, it must be taken into account that any increase in temperature is always accompanied by an increase in the excretion of β 2 -microglobulin in the urine.

Medium molecules of blood and urine

Medium molecules (MM), otherwise called protein toxins, are substances with a molecular weight of 500-5000 daltons. Their physical structure is unknown. The composition of SM includes at least 30 peptides: oxytocin, vasopressin, angiotensin, glucagon, adrenocorticotropic hormone (ACTH), etc. Excessive accumulation of SM is observed with a decrease in kidney function and a large amount of deformed proteins and their metabolites in the blood. They have a diverse biological effect and are neurotoxic, cause secondary immunosuppression, secondary anemia, inhibit protein biosynthesis and erythropoiesis, inhibit the activity of many enzymes, and disrupt the phases of the inflammatory process.

The level of SM in blood and urine is determined by a screening test, as well as by spectrophotometry in the ultraviolet zone at wavelengths of 254 and 280 mm on a DI-8B spectrophotometer, as well as dynamic spectrophotometry with computer processing in the wavelength range 220-335 nm on the same spectrometer from Beckman . The content of SM in the blood is taken as the norm equal to 0.24 ± 0.02 arb. units, and in urine - 0.312 ± 0.09 arb. units
Being normal waste products of the body, they are normally removed from it at night by glomerular filtration by 0.5%; 5% of them are disposed of in other ways. All SM fractions undergo tubular reabsorption.

Non-plasma (tissue) uroproteins

In addition to blood plasma proteins, there may be non-plasma (tissue) proteins in the urine. According to Buxbaum and Franklin (1970), non-plasma proteins account for approximately 2/3 of all urine biocolloids and a significant part of uroproteins in pathological proteinuria. Tissue proteins enter the urine directly from the kidneys or organs anatomically associated with the urinary tract, or enter the blood from other organs and tissues, and from it through the basement membranes of the glomeruli of the kidney into the urine. In the latter case, excretion of tissue proteins into the urine occurs similarly to the excretion of plasma proteins of various molecular weights. The composition of non-plasma uroproteins is extremely diverse. Among them are glycoproteins, hormones, antigens, enzymes.

Tissue proteins in urine are detected using conventional methods of protein chemistry (ultracentrifugation, gel chromatography, various types of electrophoresis), specific reactions to enzymes and hormones, and immunological methods. The latter also make it possible to determine the concentration of non-plasma uroprotein in the urine and, in some cases, to determine the tissue structures that became the source of its appearance. The main method for detecting non-plasma protein in urine is immunodiffusion analysis with antiserum obtained by immunizing experimental animals with human urine and subsequently depleted (adsorbed) by blood plasma proteins.

Study of enzymes in blood and urine

During the pathological process, profound disturbances in the vital functions of cells are observed, accompanied by the release of intracellular enzymes into the body fluids. Enzymatic diagnostics is based on the determination of a number of enzymes released from the cells of the affected organs and not characteristic of blood serum.
Studies of the human and animal nephron have shown that in its individual parts there is high enzymatic differentiation, closely related to the functions that each section performs. The glomeruli of the kidney contain relatively small amounts of various enzymes.

The cells of the renal tubules, especially the proximal parts, contain the maximum amount of enzymes. Their high activity is observed in the loop of Henle, straight tubules and collecting ducts. Changes in the activity of individual enzymes in various kidney diseases depend on the nature, severity and localization of the process. They are observed before the appearance of morphological changes in the kidneys. Since the content of various enzymes is clearly localized in the nephron, the determination of one or another enzyme in the urine can contribute to the topical diagnosis of the pathological process in the kidneys (glomeruli, tubules, cortex or medulla), the differential diagnosis of renal diseases and the determination of the dynamics (attenuation and exacerbation) of the process in the renal parenchyma.

For the differential diagnosis of diseases of the genitourinary system, determination of the activity of the following enzymes in the blood and urine is used: lactate dehydrogenase (LDH), leucine aminopeptidase (LAP), acid phosphatase (AP), alkaline phosphatase (ALP), β-glucuronidase, glutamine-oxaloacetic transaminase (GAST) , aldolase, transamidinase, etc. The activity of enzymes in blood serum and urine is determined using biochemical, spectrophotometric, chromatographic, fluorimetric and chemiluminescent methods.

Enzymuria in kidney diseases is more pronounced and natural than enzymemia. It is especially pronounced in the acute stage of the disease (acute pyelonephritis, trauma, tumor disintegration, kidney infarction, etc.). In these diseases, high activity of transamidinase, LDH, ALP and CP, hyaluronidase, LAP, as well as such nonspecific enzymes as GSH, catalase is detected [Polyantseva L.R., 1972].

Selective localization of enzymes in the nephron upon detection of PAP and alkaline phosphatase in the urine allows us to speak with confidence about acute and chronic kidney diseases (acute renal failure, necrosis of the renal tubules, chronic glomerulonephritis) [Shemetov V.D., 1968]. According to A.A. Karelin and L.R. Polyantseva (1965), transamidinase is contained in only two organs - the kidney and pancreas. It is a mitochondrial enzyme of the kidneys and is normally absent in the blood and urine. In various kidney diseases, transamidinase appears in the blood and urine, and in cases of damage to the pancreas - only in the blood.

Krotkiewski (1963) considers the activity of alkaline phosphatase in urine to be a differential test in the diagnosis of glomerulonephritis and pyelonephritis, the increase of which is more typical for pyelonephritis and diabetic glomerulosclerosis than for acute and chronic nephritis. Amylasemia increasing in dynamics with a simultaneous decrease in amylasuria may indicate nephrosclerosis and shrinkage of the kidney; PAP is of greatest importance in pathological changes in the glomeruli and convoluted tubules of the kidney, since its content in these parts of the nephron is higher [Shepotinovsky V.P. et al., 1980]. To diagnose lupus nephritis, it is recommended to determine β-glucuronidase and CP [Privalenko M.N. et al., 1974].

When assessing the role of enzymuria in the diagnosis of kidney diseases, the following points should be taken into account. Enzymes, being proteins in nature, with a low molecular weight can pass through intact glomeruli, determining the so-called physiological enzymuria. Among these enzymes, α-amylase (relative molecular weight 45,000) and uropepsin (relative molecular weight 38,000) are constantly detected in urine.

Along with low-molecular-weight enzymes, other enzymes can be found in small concentrations in the urine of healthy individuals: LDH, aspartate and alanine aminotransferases, ALP and CP, maltase, aldolase, lipase, various proteases and peptidases, sulfatase, catalase, ribonuclease, peroxidase.

High molecular weight enzymes with a relative molecular weight greater than 70,000-100,000, according to Richterich (1958) and Hess (1962), can penetrate into the urine only if the permeability of the glomerular filter is impaired. The normal content of enzymes in the urine does not allow us to exclude a pathological process in the kidney due to occlusion of the ureter. With epzymuria, enzymes can be released not only from the kidneys themselves, but also from other parenchymal organs, cells of the mucous membranes of the urinary tract, prostate gland, as well as formed elements of urine in hematuria or leukocyturia.

Most enzymes are not specific to the kidney, so it is difficult to determine where the enzymes found in the urine of healthy and sick people come from. However, the degree of enzymuria, even for nonspecific enzymes in kidney damage, is higher than normal or that observed in diseases of other organs. More valuable information can be provided by a comprehensive study of the dynamics of a number of enzymes, especially organ-specific ones, such as transaminase.

In resolving the issue of the renal origin of the enzyme in urine, the study of isoenzymes with the identification of fractions typical of the organ being studied helps. Isoenzymes are enzymes that are isogenic in action (catalyze the same reaction), but heterogeneous in chemical structure and other properties. Each tissue has a characteristic isoenzyme spectrum. Valuable methods for separating isoenzymes are starch and polyacrylamide gel electrophoresis, as well as ion exchange chromatography.

Bence Jones protein

In multiple myeloma and Waldenström macroglobulinemia, Bence-Jones protein is detected in the urine. The method for detecting the named protein in urine is based on the thermoprecipitation reaction. Previously used methods that assess the dissolution of this protein at a temperature of 100 °C and re-precipitation upon subsequent cooling are unreliable, since not all Bence-Jones protein bodies have the corresponding properties.

It is more reliable to detect this paraprotein by precipitating it at a temperature of 40 -60 ° C. However, even under these conditions, precipitation may not occur at too acidic (pH< 3,0—3,5) или слишком щелочной (рН >6.5) urine, with low TPR and low concentration of Bence-Jones protein. The most favorable conditions for its precipitation are provided by the method proposed by Patnem: 4 ml of filtered urine is mixed with 1 ml of 2 M acetate buffer pH 4.9 and heated for 15 minutes in a water bath at a temperature of 56 ° C. In the presence of Bence Jones protein, a pronounced precipitate appears within the first 2 minutes.

If the concentration of Bence Jones protein is less than 3 g/l, the test may be negative, but in practice this is extremely rare, since its concentration in urine is usually more significant. Boiling tests cannot be completely relied upon. With complete certainty, it can be detected in urine by immuno-electrophoretic method using specific sera against the heavy and light chains of immunoglobulins.

ON THE. Lopatkin

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