Your guide to protein in urine

Guide to protein in urine

Read here what proteinuria means and which therapies are possible.

Like a fine sieve, the kidneys ensure that degradation and toxins are filtered out of the blood and removed via the urine. Normally, proteins are only present in small traces. However, the Italian doctor Domenico Cotugno discovered back in 1770 that certain diseases lead to increased excretion of protein. Here you can find information about proteinuria, its causes and diagnosis.

Abstract

• The term proteinuria refers to the increased presence of proteins in the urine.
• An elevated value is defined as a quantity of more than 150 milligrams in the urine in one day or an unusual distribution of the individual protein classes.
• Proteinuria can be caused directly by kidney damage. Furthermore, infections of the urinary system and other diseases are possible triggers independent of the kidneys.
• The diagnosis is made by laboratory tests of urine samples, possibly supplemented by other tests such as blood samples or ultrasound.
• The therapy consists of treating the underlying diseases.

How does protein get into the urine?

One of the purposes of human urine is to remove toxins and waste products from the body through the kidneys. A certain amount of protein in the urine is normal and harmless. However, if the protein content exceeds the limit values, this is a sign of organic damage.

Doctors differentiate between different groups of proteins in the urine protein content – see below for more details. When interpreting the laboratory values, it is important to note whether we are talking about total protein or a specific individual value.

Causes of the disease

Doctors differentiate between variants of proteinuria depending on where it originates. The term “renal” stands for “affecting the kidney”.

• Renal proteinuria – caused by the kidneys: The so-called renal corpuscles in the renal cortex are responsible for filtering the blood for substances to be excreted. These organs each consist of a vascular bundle (glomerulus), a capsule and renal tubules. They form the barrier between the blood and urine.
  During the filtering process, proteins up to a certain molecular mass enter the urine. “Larger” proteins are retained by the glomeruli, while smaller proteins are returned to the body after filtering. However, if the membranes of the renal corpuscles are irritated or damaged, more or larger proteins enter the urine.
• Prerenal proteinuria – excess protein even before filtering: The increased protein concentration occurs independently of the work of the kidneys, for example due to an oversupply of protein in the blood (“overflow proteinuria”). This can be caused, for example, by damage to blood cells or muscle cells due to poisoning.
• Postrenal proteinuria – protein secretion after filtering: A disorder of the urinary tract can be the trigger for the abnormal values, for example inflammation.

Risk factors: Who is affected by proteinuria?

Protein in the urine is a typical consequence of these diseases and complaints:

• Diabetes
• Urinary tract infections
• High blood pressure
• Heart diseases
• Various autoimmune diseases
• Various kidney diseases
• Gout
• Overweight, obesity
• Some connective tissue diseases
• Prostatitis
• Lipometabolic diseases
• Early forms of blood cancer
• Allergies
• Side effects of medication(painkillers, antibiotics, cancer drugs) or toxins
• Viral or bacterial infections
• Pregnancy high blood pressure (pre-eclampsia)

Symptoms of excess protein in the urine

The increased protein content of the urine can hardly be recognized by the layman’s eye. The urine change as such does not cause any symptoms. Sometimes affected urine appears “foamy”.

Non-foaming urine is not an indication of normal protein levels.

Elevated levels are therefore usually only discovered by the doctor when routine checks or laboratory tests are carried out in connection with other illnesses.

Progression of proteinuria

Temporary, benign proteinuria disappears on its own without further therapy. If the change persists, medical help is required. If left untreated, renal proteinuria can lead to loss of kidney function or failure. The risk of strokes also increases if no countermeasures are taken.

Too much protein in the urine: the diagnosis

To measure the amount of protein in the urine, the doctor first uses sensitive test strips. Such rapid tests can already detect proteins and determine their quantity. If the doctor detects a significant deviation from the standard values, he or she will arrange for a thorough laboratory examination of the urine.

Before evaluating the test, the doctor should be informed of any medication currently being taken. This will enable them to classify typical side effects of the preparations.

Which proteins can be found in urine?

The protein that is particularly critical in proteinuria in the urine is the so-called albumin. In a healthy organism, albumin is almost completely retained by the kidneys during filtration. Elevated albumin levels are therefore a clear indication of a functional disorder of the renal corpuscles.

Other typical proteins in urine are globulins (storage plasma proteins) and uromodulin. The latter is produced by the kidneys themselves and is the most common protein in normal urine.

What protein levels in urine are normal?

The normal value for total protein in urine for an adult is between 60 and 150 milligrams/day.

If the proportion of albumin in the total protein is over 20 milligrams/liter, this explicitly indicates kidney disease.

How the doctor deals with too much protein in the urine

The treatment of protein in the urine depends on the amount and type of abnormal protein values detected. The laboratory results provide the doctor with information on possible causes of the disease. If necessary, he will carry out other examinations to further narrow down the diagnosis, such as ultrasound examinations, electrophoresis (analysis using electrical fields) or kidney biopsies (tissue samples).

The aim of the treatment is to cure the underlying disease that has been identified. This may involve a referral to a kidney specialist (nephrologist).

Home remedy

Supportive measures to alleviate proteinuria include drinking enough water or nettle tea, plenty of exercise and reduced protein consumption in the diet. The latter should be implemented in consultation with a nutritionist.

Prevention

If the doctor detects deviations from the norm in a urine test, it makes sense to take several follow-up samples at intervals of a few weeks in order to classify statistical “outliers” in the measured values. In this way, the attending physician can detect health risks or hidden illnesses at an early stage.

Measures that are generally regarded as health-promoting, such as reducing excess weight, giving up nicotine and alcohol and, in some cases, adjusting existing medication, make sense.

Questions and answers

When does protein in urine need to be treated?

Increased protein excretion in the urine can be a temporary and harmless event. It can be caused by stress, fever or physical exertion, for example. The patient often does not even notice such an increased protein level. If symptoms such as foamy urine persist for a longer period of time, a doctor should urgently examine and treat the triggering diseases.

How meaningful are test values for protein in urine?

Inconsistencies in the protein content in the urine can occur depending on the time of day, the season and even with measurement results from different laboratories. The values determined should not be interpreted in isolation, but in relation to the patient’s other laboratory values.

What does proteinuria mean during pregnancy?

Proteins in the urine are a typical symptom of high blood pressure during pregnancy, technically known as pre-eclampsia or gestosis. Monitoring by the attending physician is necessary.

Sources

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• https://www.dialysecentrum.de/erhoehte-eiweissausscheidung-im-urin-proteinurie-was-bedeutet-das/?cli_action=1597829378.575
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