Protein in urine: what it means, possible causes. Why is there increased protein in urine? Infusion of parsley seeds
The presence of protein in the urine can be a signal of a malfunction of the body, since in a healthy person, when analyzing urine, it is absent or present in minimal quantities. How to decipher the analysis, and in what cases is it appropriate to use the expression “deviation from the norm”? Let's look further.
Protein levels in urine - what do they mean?
The indicators by which the presence of protein in urine is determined depend on how much protein in milligrams is excreted in the urine per day:- Within 30-300 mg - indicate microalbuminuria, that is, the presence in the urine of one type of blood protein - albumin. This diagnosis may indicate earlier kidney damage or become a reason to suspect diabetes mellitus and hypertension;
- From 300 mg per dose to 1 gram per day – this is a mild degree of proteinuria. It occurs in patients with inflammatory processes in the urinary tract, chronic nephritis, and urolithiasis;
- From 1 gram to 3 grams of protein in urine per day – they talk about moderate proteinuria, which is diagnosed in acute tubular necrosis and hepatorenal syndrome;
- From 3 grams per day – this means the patient has severe proteinuria. This means that the patient's glomerular filtration barrier function in relation to protein size is impaired or the patient suffers from nephrotic syndrome.
The normal levels do not differ depending on a person’s gender, which means that the normal level of protein in the urine of adult women and men is the same and amounts to up to 0.033 g/l.
Any deviations from the norm are a reason to undergo a full examination in order to exclude or prevent the risk of developing such serious diseases as diabetes, heart failure, nephrotic syndrome and kidney disease.
Causes of protein in urine
The following common causes of protein in the urine are considered:- arterial hypertension at a progressive level;
- inflammatory or;
- mechanical damage to the kidneys;
- prolonged exposure to the cold;
- poisoning by toxins;
- high severity burns;
- cancer or tumor diseases of the kidneys.
You should not try to diagnose yourself. Only a qualified doctor can determine the exact cause of the appearance of protein in the urine.
Symptoms of increased protein in urine
As a rule, the presence of protein in urine does not have its own symptoms. You can even say that protein in the urine is a symptom that signals a malfunction of an organ such as the kidneys. Proteinuria can only manifest itself with a concomitant disease or with a pathological condition.But, proteinuria may be accompanied by symptoms that indicate problems with the kidneys. These symptoms include:
- Painful sensations in the hands;
- Anemia (see also - ?);
- Fatigue and decreased performance;
- Edema;
- Chills and high fever;
- Decreased appetite;
- Nausea and vomiting;
- Change in urine color;
- Drowsiness ().
Finding one of the above symptoms should be a reason to consult a doctor and give all the necessary tests, including a urine test.
Protein in a child's urine
Young children, as I rule, if there are no other indications for this test, donate urine during the vaccination period twice a year. The results of the analysis are interpreted as follows:
- Normal indicators can be considered if the level of protein in the urine does not exceed 0.036 g/l;
- When this indicator increases to 1 g/l per day, we can already talk about moderate proteinuria;
- When a urine test shows a protein level of 3 g/l or higher, this is severe proteinuria, which means the development of some kind of kidney or urinary tract disease.
Protein in urine in pregnant women
There are often cases when protein is found in urine in women who are expecting the birth of a baby. The causes of this phenomenon can be temporary (external factors) or permanent (inflammatory processes).
The main reasons for the appearance of protein in the urine of women during pregnancy include:
But gestosis can cause dysfunction of the placenta, which will lead to the fact that the fetus in the womb will not be able to receive enough food and oxygen for full development. This condition is dangerous because it does not manifest itself outwardly, that is, a pregnant woman may not even be aware of the presence of this problem.
It is important to understand that during pregnancy, all test readings can change every day. Thus, it is possible to determine that protein in the urine of pregnant women indicates the development of pathology only after a complete examination.
Often, by the time of birth, the protein in the urine is completely gone, and the mother meets her baby in this world already completely healthy and strong.
How to take a urine test correctly?
Its reliability depends on how urine is collected for analysis. Only urine collected in the morning, and on an empty stomach, will be suitable for analysis.For analysis, you need to prepare a container for urine - a special jar with a wide neck. It can be bought at a pharmacy. But, even if the container was purchased at a pharmacy, it must be thoroughly washed and dried before analysis.
If a urine test is required for an infant, a special urine bag can be used as a container for urine. Such bags are put on the child’s genitals under a diaper.
You cannot use the contents of unscrewed diapers for urine analysis, as this will not bring a reliable result.
The genitals of both adults and children must be clean. Therefore, before urinating, you should wash yourself using soap.
All these procedures are done in the morning, immediately after waking up. The day before, it is not recommended to eat fried foods, as well as foods that contain a lot of protein.
Treatment of increased protein in urine
Only by establishing the exact cause of proteinuria can effective treatment be selected. For example, if a patient is diagnosed with diabetes, he is prescribed a special diet. If you do not follow this diet, your blood protein levels will either remain the same or increase, which can lead to serious problems with your kidneys.The doctor prescribes individual treatment, which depends on the stage of a particular disease, how it progresses and what is caused.
It is impossible to find treatment options on your own, but you can take some measures to reduce protein levels in your urine. Such measures include folk methods to reduce the level of protein in urine.
Cranberry juice
Squeeze the juice out of a handful of cranberries and cook the skins of the berries for 15-20 minutes. Wait until the resulting broth has cooled and add berry juice to it. For sweetness you can add 1 tsp. honey or granulated sugar. Drink fruit juice a few minutes before breakfast.Parsley seed infusion
20 grams of parsley seeds should be crushed and poured with a glass of boiling water. This drink is infused for 2 hours, after which it must be drunk throughout the day, dividing the entire volume received into several doses.Birch buds
Pour 2 tablespoons of birch buds into a glass of plain water and bring to a boil. While the broth is hot, pour it into a thermos and leave for an hour and a half. When the decoction is infused, it should be taken 3 times a day, 50 grams.Fir bark tincture
The third part of a 1 liter jar should be filled with fir bark. Fill the rest of the jar with boiling water. This medicine should be infused only in a water bath for 1 hour. You need to take 50 grams of infusion half an hour before each meal.Decoctions for prevention
It is also appropriate to take various herbal tinctures as preventive measures. The most suitable are decoctions made from corn, oats, pumpkin seeds and golden mustache leaves.In a general urine test, there must be a point - protein. A person begins to worry when he receives results with increased levels of it. Why is protein present, what does this mean, what levels of protein in urine are acceptable? In order to deal with this issue, you will have to go to the doctor.
Where does it come from?
This component is constituent element of enzymes, and takes part in almost all cellular processes occurring in the body. Therefore, in some quantities its formation in urine is quite acceptable, as is its absence.
Even eating large amounts of protein foods can affect. But the protein concentration quickly disappears.
Important! Despite the fact that approximately 15 percent of healthy people sometimes have protein in their urine, a negative test result is still considered the absolute norm.
The body is protected from protein entering the urethra by the so-called renal pelvis, which serve as a “wall”. Therefore, damage to this protection can cause protein formation.
In medicine, an increase in concentration is called proteinuria.
How much protein should there be in urine - acceptable standards
This is the first indicator that the doctor looks at when interpreting the results of a patient’s examination. It is impossible to visually determine the presence of protein in urine. One can only guess from the presence in it whitish impurities.
The analysis is carried out using various methods: boiling test, test strips, Brandberg-Roberts-Stolnikov study, as well as quantitative methods. Take a morning portion of the material or a daily dose.
If a protein is detected, repeated screening is carried out in two weeks, due to existing provoking factors such as nervous tension, protein foods in the diet, hypothermia.
Norms of protein in urine in women and men:
morning analysis - 0.033 g/l
daily analysis - 0.06 g/l
Norms of protein in urine in children:
morning analysis - 0.037 g/l
daily analysis - 0.07 g/l
Norms of protein in urine in pregnant women:
morning analysis - 0.033 g/l
daily analysis - 0.3 g/l
Read our article on how to lower the level of protein in your urine.
Why the norm is increased - causes of proteinuria
The reasons for the increase in protein are varied. In addition to physiological reasons, including recent acute respiratory viral infections, pregnancy, prolonged exposure to the sun, improper hygiene, etc., if there is a lot of protein in the urine, this may be a consequence of diseases:
- Urinary system;
- Complications of ARVI: influenza, pneumonia;
- Allergy;
- Pyelonephritis;
- Diabetes mellitus;
- Systemic diseases;
- Nephropathy;
- Malignant neoplasms.
In newborns, immediately after birth, there is a slight increase in protein in the urine. And it's perfect Fine.
Even a passion for proteins, a lack of water in the body, or taking high doses of vitamin C can lead to the fact that protein can “jump” to significant numbers.
Symptoms of pathology
Proteinuria is divided according to severity: traces of protein - up to 0.033; light – up to 1; moderate – up to 2 and severe – more than 3.
If the excess is insignificant, then an adult does not notice any signs. But the following symptoms may appear:
Symptoms of severe proteinuria include increased blood pressure, migraines, and sweating. If there is unpleasant odor in urine, then this indicates the progression of a pathology, for example, urethritis.
Protein in urine 0,066 - such indicators are a common occurrence during pregnancy, and are called gestational proteinuria. If there are no others, and the remaining values in the analyzes are normal, then there is no need to worry.
Protein in urine 0,033 - specialists note in the analysis - traces of protein in the urine, or trace proteinuria. Failure can occur in healthy people and does not mean kidney disease at all, especially if there are no additional signs of the disease. Reasons:
- Poor nutrition;
- Stress;
- Use of certain types of antibiotics.
The result is distorted by incorrect urine collection, that is, poor hygiene, etc.
You need to retake the test again.
Protein in urine 0,1 - indicates that there is moderate proteinuria. For pregnant women it can be regarded as the norm.
But the doctor must evaluate all indicators and prescribe additional studies to detect a kidney problem early: general blood test (it will show increased leukocytes and ESR), creatinine, urea, C-reactive protein. If necessary, an ultrasound of the kidneys, in women an additional ultrasound of the pelvic organs.
Protein for various diseases
Increased protein in the urine is a constant companion to pathologies such as cystitis, diabetes mellitus and pyelonephritis.
Acute cystitis affects people of almost all ages, but most often “loves” the fair sex. Diagnosis is based on proteinuria above 1 g/l and detection of increased leukocytes in the urine.
Plus the patient’s complaints about the strong smell of urine, painful urination and general symptoms of malaise. The patient is prescribed antibiotics and diet. It is prohibited to consume products that may provoke even greater protein growth: This is meat, fatty fish, food excessively rich in vitamin C.
Diabetics are at high risk of complications from their underlying disease: kidney dysfunction. Therefore, they need to monitor protein in their urine at least once every six months. Experts are sounding the alarm already at this figure above 0.3 g/l. Albumin protein is determined. Its norms for patients with diabetes mellitus:
- Less than 20 mg/l is normal;
- 20-200 mg/l – slight excess;
- Above 200 – proteinuria.
To diagnose pyelonephritis, each analysis value is not assessed separately. But the characteristic picture of urine is: a pale tint, and if pus appears, it looks cloudy. White blood cells are high - more than 6 (in children the norm is up to 6). Protein is usually above 1 g/l. But density and acidity may be within normal limits.
The clinical picture of the patient’s complaints: high fever, pain in the lower back, when urinating, weakness.
Why is proteinuria dangerous?
This pathology is fraught with the body losing various types of protein that are important for its life. As a result, for a person this will result in constant swelling, problems with blood clotting, and therefore a high risk of bleeding. In addition, problems may appear with the thyroid gland and, in fact, with any organ or system of the body.
Find out what the unpleasant smell of urine means from the video:
[06-038 ] Total protein in urine
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This is a clinical and laboratory sign of kidney damage, used to diagnose kidney diseases and monitor treatment.
SynonymsEnglish
Urine total protein, urine protein, 24-Hour Urine Protein.
Research method
Colorimetric photometric method.
Units of measurement
G/l (grams per liter), g/day. (grams per day).
What biomaterial can be used for research?
The average portion of morning urine, daily urine.
How to properly prepare for research?
- Do not drink alcohol for 24 hours before the test.
- Avoid taking diuretics for 48 hours before donating urine (in consultation with your doctor).
General information about the study
Total protein in urine is an early and sensitive sign of primary kidney diseases and secondary nephropathies in systemic diseases. Normally, only a small amount of protein is lost in the urine due to the filtration mechanism of the renal glomerulus - a filter that prevents the penetration of large charged proteins into the primary filtrate. While low molecular weight proteins (less than 20,000 daltons) freely pass through the glomerular filter, the supply of high molecular weight albumin (65,000 daltons) is limited. Most of the protein is reabsorbed into the bloodstream in the proximal tubules of the kidney, with the result that only a small amount is ultimately excreted in the urine. About 20% of the protein secreted normally is low molecular weight immunoglobulins, and 40% each is albumin and mucoproteins secreted in the distal renal tubules. Normal protein loss is 40-80 mg per day, the release of more than 150 mg per day is called proteinuria. In this case, the main amount of protein is albumin.
It should be noted that in most cases, proteinuria is not a pathological sign. Protein in the urine is detected in 17% of the population and only 2% of them cause serious illness. In other cases, proteinuria is considered functional (or benign); it is observed in many conditions, such as fever, increased physical activity, stress, acute infectious disease, and dehydration. Such proteinuria is not associated with kidney disease, and protein loss is insignificant (less than 2 g/day). One of the types of functional proteinuria is orthostatic (postural) proteinuria, when protein in the urine is detected only after prolonged standing or walking and is absent in a horizontal position. Therefore, with orthostatic proteinuria, an analysis of total protein in the morning urine will be negative, and an analysis of 24-hour urine will reveal the presence of protein. Orthostatic proteinuria occurs in 3-5% of people under 30 years of age.
Protein in the urine also appears as a result of its excess production in the body and increased filtration in the kidneys. In this case, the amount of protein entering the filtrate exceeds the possibilities of reabsorption in the renal tubules and is ultimately excreted in the urine. This “overflow” proteinuria is also not associated with kidney disease. It can accompany hemoglobinuria with intravascular hemolysis, myoglobinuria with muscle tissue damage, multiple myeloma and other plasma cell diseases. With this type of proteinuria, it is not albumin that is present in the urine, but some specific protein (hemoglobin in hemolysis, Bence Jones protein in myeloma). In order to identify specific proteins in urine, a 24-hour urine test is used.
For many kidney diseases, proteinuria is a characteristic and constant symptom. According to the mechanism of occurrence, renal proteinuria is divided into glomerular and tubular. Proteinuria, in which protein in the urine appears as a result of damage to the basement membrane, is called glomerular. The glomerular basement membrane is the main anatomical and functional barrier to large and charged molecules; therefore, when it is damaged, proteins freely enter the primary filtrate and are excreted in the urine. Damage to the basement membrane can occur primarily (in idiopathic membranous glomerulonephritis) or secondary, as a complication of a disease (in diabetic nephropathy due to diabetes mellitus). The most common is glomerular proteinuria. Diseases accompanied by damage to the basement membrane and glomerular proteinuria include lipoid nephrosis, idiopathic membranous glomerulonephritis, focal segmental glomerular sclerosis and other primary glomerulopathies, as well as diabetes mellitus, connective tissue diseases, post-streptococcal glomerulonephritis and other secondary glomerulopathies. Glomerular proteinuria is also characteristic of kidney damage associated with certain medications (non-steroidal anti-inflammatory drugs, penicillamine, lithium, opiates). The most common cause of glomerular proteinuria is diabetes mellitus and its complication – diabetic nephropathy. The early stage of diabetic nephropathy is characterized by the secretion of a small amount of protein (30-300 mg/day), the so-called microalbuminuria. As diabetic nephropathy progresses, protein loss increases (macroalbuminemia). The degree of glomerular proteinuria varies, often exceeding 2 g per day and can reach more than 5 g of protein per day.
When protein reabsorption function in the renal tubules is impaired, tubular proteinuria occurs. As a rule, protein loss with this option does not reach such high values as with glomerular proteinuria, and amounts to up to 2 g per day. Impaired protein reabsorption and tubular proteinuria are accompanied by hypertensive nephroangiosclerosis, urate nephropathy, intoxication with lead and mercury salts, Fanconi syndrome, as well as drug-induced nephropathy when using non-steroidal anti-inflammatory drugs and some antibiotics. The most common cause of tubular proteinuria is hypertension and its complication – hypertensive nephroangiosclerosis.
An increase in protein in the urine is observed in infectious diseases of the urinary system (cystitis, urethritis), as well as in renal cell carcinoma and bladder cancer.
The loss of a significant amount of protein in the urine (more than 3-3.5 g/l) leads to hypoalbuminemia, a decrease in blood oncotic pressure and both external and internal edema (edema of the lower extremities, ascites). Significant proteinuria provides an unfavorable prognosis for chronic renal failure. Persistent loss of small amounts of albumin does not cause any symptoms. The danger of microalbuminuria is the increased risk of coronary heart disease (especially myocardial infarction).
Quite often, as a result of a variety of reasons, the analysis of morning urine for total protein is false positive. Therefore, proteinuria is diagnosed only after repeated analysis. If two or more tests of the morning urine sample are positive for total protein, proteinuria is considered persistent, and the examination is supplemented by an analysis of 24-hour urine for total protein.
Testing morning urine for total protein is a screening method for detecting proteinuria. It does not allow assessment of the degree of proteinuria. In addition, the method is sensitive to albumin, but does not detect low molecular weight proteins (for example, Bence Jones protein in myeloma). In order to determine the degree of proteinuria in a patient with a positive morning urine sample for total protein, 24-hour urine is also tested for total protein. If multiple myeloma is suspected, 24-hour urine is also analyzed, and it is necessary to conduct additional research for specific proteins - electrophoresis. It should be noted that analysis of 24-hour urine for total protein does not differentiate the variants of proteinuria and does not reveal the exact cause of the disease, so it must be supplemented with some other laboratory and instrumental methods.
What is the research used for?
- For the diagnosis of lipoid nephrosis, idiopathic membranous glomerulonephritis, focal segmental glomerular sclerosis and other primary glomerulopathies.
- For the diagnosis of kidney damage in diabetes mellitus, systemic connective tissue diseases (systemic lupus erythematosus), amyloidosis and other multiorgan diseases with possible kidney involvement.
- For the diagnosis of kidney damage in patients at increased risk of chronic renal failure.
- To assess the risk of developing chronic renal failure and coronary heart disease in patients with kidney disease.
- To assess renal function during treatment with nephrotoxic drugs: aminoglycosides (gentamicin), amphotericin B, cisplatin, cyclosporine, non-steroidal anti-inflammatory drugs (aspirin, diclofenac), ACE inhibitors (enalapril, ramipril), sulfonamides, penicillin, thiazide, furosemide and some others.
When is the study scheduled?
- For symptoms of nephropathy: edema of the lower extremities and periorbital region, ascites, weight gain, arterial hypertension, micro- and gross hematuria, oliguria, increased fatigue.
- For diabetes mellitus, systemic connective tissue diseases, amyloidosis and other multi-organ diseases with possible kidney involvement.
- With existing risk factors for chronic renal failure: arterial hypertension, smoking, heredity, age over 50 years, obesity.
- When assessing the risk of developing chronic renal failure and coronary heart disease in patients with kidney disease.
- When prescribing nephrotoxic drugs: aminoglycosides, amphotericin B, cisplatin, cyclosporine, non-steroidal anti-inflammatory drugs, ACE inhibitors, sulfonamides, penicillins, thiazide diuretics, furosemide and some others.
What do the results mean?
Reference values (average morning urine sample)
Concentration:
Reference values (daily urine)
Highlight:
after heavy physical activity
Reasons for increased levels of total protein in urine:
1. Kidney diseases:
- primary kidney diseases: lipoid nephrosis, idiopathic membranous glomerulonephritis, focal segmental glomerular sclerosis, IgA glomerulonephritis, membranoproliferative glomerulonephritis, pyelonephritis, Fanconi syndrome, acute tubulointerstitial nephritis;
- kidney damage in systemic diseases: diabetes mellitus, arterial hypertension, systemic connective tissue diseases, amyloidosis, post-streptococcal glomerulonephritis, preeclampsia, urate nephropathy, malignant neoplasms (lungs, gastrointestinal tract, blood), sickle cell anemia, etc.;
- kidney damage during treatment with nephrotoxic drugs: aminoglycosides, amphotericin B, cisplatin, cyclosporine, non-steroidal anti-inflammatory drugs, ACE inhibitors, sulfonamides, penicillins, thiazides, furosemide and some others;
- kidney damage due to poisoning with lead and mercury salts;
- renal cell carcinoma.
2. Increased protein production and filtration in the body (overflow proteinuria):
- multiple myeloma, Waldenström's macroglobulinemia;
- hemoglobinuria with intravascular hemolysis;
- myoglobinuria due to damage to muscle tissue.
3. Transient (benign) proteinuria.
One of the abnormalities in a general urine test is the presence of elevated protein levels.
A more accurate determination of the protein composition of urine allows us to obtain a biochemical study of urine. This condition is referred to as proteinuria or albuminuria.
In healthy people, protein in the urine should be absent or detected in extremely small quantities. Therefore, if a high level of protein is detected in the urine, immediate additional diagnostics are required.
Protein in urine - what does it mean?
Most often, increased protein in the urine appears due to inflammatory processes in the urinary system. This usually means that the filtration function of the kidneys is impaired as a result of partial destruction of the renal pelvis.
However, this is not always the case. Sometimes proteinuria appears in completely healthy kidneys. This may be increased sweating at elevated temperatures, when a person is sick with the flu or, increased physical activity, or eating a large amount of protein food on the eve of the test.
Physiological and functional proteinuria
Physiological proteinuria is characterized by an increase in the protein content in morning urine to a level not exceeding 0.033 g/l.
So, why might protein appear in the urine? This such factors contribute:
- heavy physical activity;
- excessive insolation;
- hypothermia;
- increased levels of norepinephrine and adrenaline in the blood;
- excessive consumption of protein foods;
- stressful conditions;
- prolonged palpation examination of the kidneys and abdomen.
A physiological increase in protein content in the urine of a child or an adult is not a cause for concern and does not require special treatment.
Causes of increased protein in urine
A high amount of protein in the urine is one of the undoubted signs of a disruption in the normal functioning of the kidneys caused by some disease. An increase in the amount of protein in the urine can be accompanied by various diseases - they are considered the main reason for the increase in protein in the urine.
Such diseases include:
- polycystic kidney disease;
- glomerulonephritis;
- amyloidosis and renal tuberculosis.
The kidneys can be affected secondarily in certain pathologies of other organs and systems of the body. More often renal functions are impaired when:
- gestosis of pregnant women (nephropathy);
- atherosclerosis of the renal arteries.
Another group of reasons explaining why protein appears in the urine is inflammatory diseases of the lower urinary tract and genital area:
- inflammation of the ureters;
- , vulvovaginitis in women.
These are the most common causes of protein in urine. Only by conducting a more in-depth diagnosis can you determine why there is a lot of protein in the urine, and what this means in your particular case.
Normal level of proteins in urine
If the patient is preparing to take a protein test, he should not take acetazolamide, colistin, aminoglycoside and other drugs the day before. They directly affect the concentration of protein in the urine.
Healthy people should not have it. It happens that only a small amount appears. If the concentration in the body is no more than 0.03 g/l, then this is not scary. But if you deviate from this norm, you should worry.
Proteinuria is the detection of protein in the urine in concentrations exceeding 0.033 grams/liter. Taking into account the daily fluctuations in the excretion (excretion) of protein in the urine (the maximum amount occurs during the daytime), to assess the extent of proteinuria, a 24-hour urine analysis is performed, which makes it possible to determine the daily proteinuria.
Based on global medical standards, proteinuria is divided into several forms:
- 30-300 mg/day of protein – this condition is called microalbuminuria.
- 300 mg – 1 g/day – mild proteinuria.
- 1 g – 3 g/day – average form.
- Over 3000 mg/day is a severe stage of the disease.
In order for the tests to be correct and error-free, urine should be collected correctly. As a rule, collection is carried out in the morning, when you have just woken up.
Symptoms
A temporary increase in the level of proteins in urine does not give any clinical picture and very often occurs without symptoms.
Pathological proteinuria is a manifestation of the disease that contributed to the formation of protein molecules in the urine. With a prolonged course of this condition, patients, regardless of their age (children and adolescents, women, men), have the following symptoms:
- pain and aches in joints and bones;
- swelling, hypertension (signs of developing nephropathy);
- , detection of flakes and white deposits in the urine;
- muscle soreness, cramps (especially at night);
- pale skin, weakness, apathy (symptoms of anemia);
- disturbances of sleep, consciousness;
- fever, lack of appetite.
If you show an increased amount of protein, then you should definitely repeat the test within one to two weeks.
Protein in urine during pregnancy
The detection of protein in the urine in the early stages of pregnancy may be a sign of a hidden kidney pathology that the woman had before pregnancy. In this case, the entire pregnancy must be monitored by specialists.
Protein in the urine in the second half of pregnancy may appear in small quantities due to mechanical compression of the kidneys by the growing uterus. But it is necessary to exclude kidney diseases and gestosis in pregnant women.
Why is high protein in urine dangerous?
Proteinuria can be manifested by the loss of various types of protein, so the symptoms of protein deficiency are also varied. With the loss of albumin, the oncotic pressure of the plasma decreases. This manifests itself in edema, the occurrence of orthostatic hypotension and an increase in lipid concentrations, which can only be reduced if the protein composition in the body is corrected.
With excessive loss of proteins that make up the complement system, resistance to infectious agents disappears. When the concentration of procoagulant proteins decreases, blood clotting ability is impaired. What does it mean? This significantly increases the risk of spontaneous bleeding, which is life-threatening. If proteinuria consists of a loss of thyroxine-binding globulin, then the level of free thyroxine increases and functional hypothyroidism develops.
Since proteins perform many important functions (protective, structural, hormonal, etc.), their loss during proteinuria can have negative consequences on any organ or system of the body and lead to disruption of homeostasis.
Treatment
So, the possible causes of protein in the urine have already been clarified and now the doctor must prescribe appropriate treatment for the disease. It is wrong to say that it is necessary to treat protein in the urine. After all, proteinuria is just a symptom of the disease, and the doctor must eliminate the cause that caused this symptom.
As soon as effective treatment of the disease begins, the protein in the urine will gradually disappear completely or its amount will sharply decrease. Physiological and orthostatic proteinuria do not require treatment at all.
Proteinuria is a phenomenon in which protein is detected in the urine, which indicates the possibility of kidney damage and serves as a factor in the development of diseases of the heart, blood vessels, and lymphatic vessels.
What does protein in urine mean (proteinuria)
Detection of protein in urine does not always indicate illness. This phenomenon is typical even for absolutely healthy people, in whose urine protein can be detected. Hypothermia, physical activity, and consumption of protein foods lead to the appearance of protein in the urine, which disappears without any treatment.
During screening, protein is detected in 17% of apparently healthy people, but only 2% of this number of people have a positive test result as a sign of kidney disease.
Protein molecules should not enter the blood. They are vitally necessary for the body - they are building materials for cells, and participate in reactions as coenzymes, hormones, and antibodies. For both men and women, the norm is a complete absence of protein in the urine.
The function of preventing the body from losing protein molecules is performed by the kidneys.
There are two kidney systems that filter urine:
- renal glomeruli - do not allow large molecules to pass through, but do not retain albumin, globulins - a small fraction of protein molecules;
- renal tubules - adsorb proteins filtered by the glomeruli and return them back to the circulatory system.
Mucoproteins and globulins are found in urine (about 49%), of which immunoglobulins account for about 20%.
Globulins are whey proteins with a large molecular weight that are produced in the immune system and liver. Most of them are synthesized by the immune system and are classified as immunoglobulins or antibodies.
Albumin is a fraction of proteins that first appear in the urine even with minor kidney damage. A certain amount of albumin is also present in healthy urine, but it is so insignificant that it is not detected by laboratory diagnostics.
The lower threshold that can be detected using laboratory diagnostics is 0.033 g/l. If more than 150 mg of protein is lost per day, then they speak of proteinuria.
Basic information about protein in urine
Symptoms of protein in urine
The disease with mild proteinuria is asymptomatic. Visually, urine that does not contain protein cannot be distinguished from urine, which contains a small amount of protein. Urine becomes somewhat foamy with a high degree of proteinuria.
Active excretion of protein in the urine can be assumed based on the patient’s appearance only in cases of moderate or severe disease due to the appearance of swelling of the limbs, face, and abdomen.
In the early stages of the disease, indirect signs of proteinuria may include the following symptoms:
- changes in urine color;
- increasing weakness;
- lack of appetite;
- nausea, vomiting;
- bone pain;
- drowsiness, dizziness;
- elevated temperature.
The appearance of such signs cannot be ignored, especially during pregnancy. This may mean a slight deviation from the norm, or it may be a symptom of developing gestosis, preeclampsia.
Diagnostics
Quantifying protein loss is not an easy task; several laboratory tests are used to achieve a more complete picture of the patient’s condition.
Difficulties in choosing a method for detecting excess protein in urine are explained by:
- low protein concentration, which requires high-precision instruments to recognize;
- the composition of urine, which complicates the task, since it contains substances that distort the result.
How to prepare for tests
The most information can be obtained by analyzing the first morning portion of urine, which is collected after waking up.
On the eve of the analysis, the following conditions must be met:
- do not consume spicy, fried, protein foods, alcohol;
- Avoid taking diuretics 48 hours before;
- limit physical activity;
- carefully observe the rules of personal hygiene.
Morning urine is the most informative, since it stays in the bladder for a long time and is less dependent on food intake.
You can analyze the amount of protein in urine using a random portion, which is taken at any time, but such an analysis is less informative and the likelihood of error is higher.
To quantify daily protein losses, an analysis of total daily urine is performed. To do this, collect all urine excreted during the day into a special plastic container within 24 hours. You can start collecting at any time. The main condition is exactly one day of collection.
Qualitative diagnostic methods
The qualitative definition of proteinuria is based on the ability of protein to denature under the influence of physical or chemical factors. Qualitative methods are screening methods that allow one to determine the presence of protein in the urine, but do not make it possible to accurately assess the degree of proteinuria.
Samples used:
- with boiling;
- sulfosalicylic acid;
- nitric acid, Larionova reagent with ring Heller test.
A test with sulfosalicylic acid is performed by comparing a control urine sample with an experimental one, in which 7-8 drops of 20% sulfosalicylic acid are added to the urine. The presence of protein is inferred from the intensity of the opalescent turbidity that appears in the test tube during the reaction.
The Heller test using 50% nitric acid is more often used. The sensitivity of the method is 0.033 g/l. At this protein concentration, a white thread-like ring appears in a test tube with a urine sample and reagent 2-3 minutes after the start of the experiment, the formation of which indicates the presence of protein.
Heller's test 
Semi-quantitative
Semi-quantitative methods include:
- method for determining protein in urine using test strips;
- Brandberg-Roberts-Stolnikov method.
The Brandberg-Roberts-Stolnikov method of determination is based on the Heller ring method, but allows a more accurate assessment of the amount of protein. When performing a test using this method, several dilutions of urine are used to achieve the appearance of a thread-like protein ring in a time interval between 2-3 minutes from the start of testing.
In practice, the test strip method is used with bromophenol blue dye applied as an indicator. The disadvantage of test strips is their selective sensitivity to albumin, which leads to distorted results if the concentration of globulins or other proteins in the urine increases.
The disadvantages of the method also include the relatively low sensitivity of the test to protein. Test strips begin to react to the presence of protein in urine when the protein concentration exceeds 0.15 g/l.
Quantitative assessment methods
Quantitative assessment methods can be divided into:
- turbidimetric;
- colorimetric.
Turbidimetric techniques
The methods are based on the property of proteins to reduce solubility under the influence of a binding agent to form a poorly soluble compound.
Agents that cause protein binding can be:
- sulfosalicylic acid;
- trichloroacetic acid;
- benzethonium chloride.
Conclusions are drawn about the test results based on the degree of attenuation of the light flux in the sample with the suspension compared to the control. The results of this method cannot always be considered reliable due to differences in operating conditions: the rate of mixing of reagents, temperature, and acidity of the medium.
Taking medications the day before affects the assessment; before conducting tests using these methods, you should not take:
- antibiotics;
- sulfonamides;
- iodine-containing drugs.
The method is affordable, which allows it to be widely used for screening. But more accurate results can be obtained using more expensive colorimetric techniques.
Colorimetric methods
Sensitive methods that allow accurate determination of protein concentration in urine include colorimetric techniques.
This can be done with high accuracy:
- biuret reaction;
- Lowry technique;
- staining techniques that use dyes that form complexes with urine proteins that are visually different from the sample.
Colorimetric methods for detecting protein in urine 
Biuret reaction
The method is reliable and highly sensitive, allowing the determination of albumin, globulins, and paraproteins in urine. It is used as the main way to clarify controversial test results, as well as daily protein in the urine of patients in nephrology departments of hospitals.
Lowry method
Even more accurate results can be achieved by the Lowry method, which is based on the biuret reaction, as well as the Folin reaction, which recognizes tryptophan and tyrosine in protein molecules.
To eliminate possible errors, the urine sample is purified from amino acids and uric acid using dialysis. Errors are possible when consuming salicylates, tetracyclines, and chlorpromazine.
Staining techniques
The most accurate way to determine a protein is based on its ability to bind to dyes, of which the following are used:
- Ponceau;
- Coomassie brilliant blue;
- pyrogallic red.
Daily proteinuria
The amount of protein excreted in urine varies throughout the day. To more objectively assess protein loss in urine, the concept of daily protein in urine is introduced. This value is measured in g/day.
To quickly assess daily protein in urine, the amount of protein and creatinine is determined in a single portion of urine, then based on the protein/creatinine ratio, a conclusion is drawn about protein loss per day.
The method is based on the fact that the rate of creatinine excretion in urine is a constant value and does not change during the day. In a healthy person, the normal protein:creatinine ratio in urine is 0.2.
This method eliminates possible errors that may occur when collecting daily urine.
Decoding the results
Qualitative tests are more likely to produce false positive or false negative results than quantitative tests. Errors arise in connection with taking medications, eating habits, and physical activity on the eve of the test.
Sulfosalicylic acid test
The interpretation of this qualitative test is given by visual assessment of turbidity in the test tube in comparison of the test result with the control:
- a weakly positive reaction is assessed as +;
- positive ++;
- strongly positive +++.
Heller's test
The Heller ring test more accurately assesses the presence of protein in the urine, but does not quantify the protein in the urine. Like the sulfosalicylic acid test, the Heller test gives only an approximate idea of the protein content in urine.
Brandberg-Roberts-Stolnikov test
The method allows you to evaluate the degree of proteinuria quantitatively, but is too labor-intensive and inaccurate, since with strong dilution the accuracy of the assessment decreases.
To calculate protein, you need to multiply the degree of urine dilution by 0.033 g/l:
| Urine volume (ml) | Water volume (ml) | Breeding | Protein content (g/l) |
|---|---|---|---|
| 1 | 1 | 1: 2 | 0,066 |
| 1 | 2 | 1: 3 | 0,099 |
| 1 | 3 | 1: 4 | 0,132 |
| 1 | 4 | 1: 5 | 0,165 |
| 1 | 5 | 1: 6 | 0,198 |
| 1 | 6 | 1: 7 | 0,231 |
| 1 | 7 | 1: 8 | 0,264 |
| 1 | 8 | 1: 9 | 0,297 |
| 1 | 9 | 1: 10 | 0,33 |
Test strip testing
The test does not require special conditions; this procedure can be easily done at home. To do this, you need to immerse the test strip in the urine for 2 minutes.
The results will be expressed by the number of pluses on the strip, the decoding of which is contained in the table:
- Test results corresponding to a value of up to 30 mg/100 ml correspond to physiological proteinuria.
- Test strip values of 1+ and 2++ indicate significant proteinuria.
- Values of 3+++, 4++++ are observed with pathological proteinuria caused by kidney disease.
Test strips can only approximately determine increased protein in the urine. They are not used for accurate diagnosis, and even more so they cannot say what it means.
Test strips do not allow adequate assessment of the amount of protein in the urine of pregnant women. A more reliable method of assessment is to determine protein in daily urine.
Determination of protein in urine using a test strip:
Total protein in urine
Daily protein in urine serves as a more accurate diagnostic assessment of the functional state of the kidneys. To do this, it is necessary to collect all the urine excreted by the kidneys per day.
Acceptable values for the protein/creatinine ratio are the data given in the table:
If you lose more than 3.5 g of protein per day, the condition is called massive proteinuria.
If there is a lot of protein in the urine, a re-examination is required after 1 month, then after 3 months, based on the results of which it is established why the norm is exceeded.
Reasons
The reasons for increased protein in the urine are its increased production in the body and impaired renal function; proteinuria is distinguished:
- physiological – minor deviations from the norm are caused by physiological processes and resolve spontaneously;
- pathological - changes are caused as a result of a pathological process in the kidneys or other organs of the body; without treatment it progresses.
Physiological proteinuria
A slight increase in protein can be observed with abundant protein nutrition, mechanical burns, injuries, accompanied by increased production of immunoglobulins.
Mild proteinuria can be caused by physical activity, psycho-emotional stress, and taking certain medications.
Physiological proteinuria refers to an increase in protein in the urine of children in the first days after birth. But after a week of life, the protein content in the child’s urine is considered as a deviation from the norm and indicates a developing pathology.
Kidney diseases and infectious diseases are also sometimes accompanied by the appearance of protein in the urine.
Such conditions usually correspond to a mild degree of proteinuria, are transient phenomena, quickly resolve on their own, without requiring special treatment.
Pathological proteinuria
More severe conditions, severe proteinuria is observed in the case of:
- diabetes;
- heart disease;
- bladder cancer;
- multiple myeloma;
- infections, drug damage, polycystic kidney disease;
- high blood pressure;
- systemic lupus erythematosus;
- Goodpasture's syndrome.
Intestinal obstruction, heart failure, and hyperthyroidism can cause traces of protein in the urine.
Classification
The types of proteinuria are classified in several ways. For a qualitative assessment of proteins, you can use the Yaroshevsky classification.
According to Yaroshevsky’s taxonomy, created in 1971, proteinuria is distinguished:
- renal - which includes impaired glomerular filtration, release of tubular protein, insufficiency of protein readsorption in the tubules;
- prerenal – occurs outside the kidneys, removal from the body of hemoglobin, proteins that appear in excess in the blood as a result of multiple myeloma;
- postrenal – occurs in the area of the urinary tract after the kidneys, protein excretion due to the destruction of the urinary organs.
To quantify what is happening, the degrees of proteinuria are conventionally distinguished. It must be remembered that they can easily become more severe without treatment.
The most severe stage of proteinuria develops with a loss of more than 3 g of protein per day. Protein loss of 30 mg to 300 mg per day corresponds to the moderate stage or microalbumnuria. Up to 30 mg of protein in daily urine means mild proteinuria.
