The detection of protein in the urine helps to identify kidney damage, for example, due to early diabetes. The test is, therefore, recommended once a year for diabetes. In the kidney corpuscles, urinary substances and liquids are filtered out of the blood into the urine. Small proteins can get into the urine, larger ones only if the membranes are damaged.

What does proteinuria mean?

One speaks of proteinuria if protein (protein) is detected in the urine. The urine is filtered out of the blood in the kidney corpuscles. There are about one million in each kidney cortex. Usually, only the smallest protein particles get into the urine (mainly albumin). With kidney damage, more and more abundant proteins are found in the urine.

How is proteinuria measured

The protein excretion can be measured with test strips that are immersed in the urine. Sensitive measuring test strips are required to detect small amounts of protein (20 to 200 mg / l). If the test is positive, a urine test in the laboratory is recommended as a check. A distinction can thus be made between microalbuminuria (20 to 200 mg / l) and macroalbuminuria (over 200 mg / l).

Why is protein measured in urine?

Examining the urine for protein substances is primarily used for the early detection of kidney damage, for example, diabetes. It is recommended for diabetes at least once a year.

Diabetic kidney damage can be assumed if two tests with an interval of two to four weeks show a protein concentration above 20 mg / l. However, other reasons can temporarily increase protein excretion, such as acute inflammation such as urinary tract infections.

Important: The reference values, as well as the determined values, can differ significantly from laboratory to laboratory. Furthermore, there may be healthy daily and (seasonal) seasonal fluctuations with no disease value. Before you become unsettled by different results, please ask your doctor to explain your data to you. Besides, individual laboratory values alone are usually not meaningful. They often have to be assessed in connection with other values and over time.

Common causes of Protein in Urine

Short-term proteinuria

  • Urinary tract infections
  • Urinary tract infections in women, urinary tract infections in men. Urinary tract infections play a unique role in pregnancy.
  • Typical symptoms include burning and discomfort when urinating and frequent urge to urinate.
  • Protein in urine is not a necessary side effect of urinary tract infections.

Inflammation of the kidney (pyelonephritis)

  • Protein in urine can occur, but it is not a necessary side effect of kidney inflammation.
  • Fever and general malaise, as well as tenderness to the kidneys, are common symptoms.
  • About a third of those affected complain of urinary tract infection symptoms such as a burning sensation when urinating.

Pregnancy

  • Protein in urine in the first half of pregnancy can be a sign of pre-existing kidney or urinary tract disease.
  • Proteinuria in the second half of pregnancy can indicate pregnancy poisoning (preeclampsia) and requires clarification.

Acute kidney failure

  • Acute kidney failure is due to suddenly impaired kidney function.
  • The symptoms are often non-specific. Decreased urine output can occur, and water can accumulate in the legs. In the case of severe proteinuria, patients sometimes observe foaming of the urine.
  • In the advanced course of the disease, symptoms like loss of appetite, nausea, vomiting, non-specific abdominal pain, and tiredness occur.
  • Persistent proteinuria

Chronic kidney failure

  • Chronic kidney failure progresses slowly and remains asymptomatic for a long time.
  • In the advanced stage, there is a complex clinical picture with symptoms from many organ systems.
  • Signs of illness are fatigue, itching, tiredness, urge to urinate at night, restless legs, shortness of breath, and pale skin color.
  • The most common causes are long-term insufficiently treated high blood pressure and type 1 or type 2 diabetes mellitus, chronic kidney infections, and inherited kidney diseases.
  • Chronic inflammation of the kidneys ( glomerulonephritis )

Proteinuria is one of the typical findings of chronic inflammation of the kidneys. Renal function is often also restricted here so that it also belongs to chronic kidney failure (see above).

Cases not requiring treatment

  • Proteinuria only during the day/afternoon (orthostatic proteinuria):
  • It is position-dependent proteinuria with increased protein excretion of up to 1-3 g during the day, resulting in otherwise healthy people.
  • When lying down at night, there is no or only minimal protein excretion.
  • The creatinine level is average and indicates normal kidney function.
  • The protein excretion is harmless.
  • Due to the good prognosis, no further examinations are necessary.

Rare Causes of Protein in Urine

Multiple myeloma

  • Multiple myeloma, also called plasmacytoma, is a cancer of the hematopoietic system.
  • Classic symptoms include pallor and poor performance due to anemia, bone pain, and infections.
  • Accompanying chronic kidney failure often occurs.

Blood cancer (leukemia)

  • oacute lymphoblastic leukemia
  • oacute myeloid leukemia
  • ochronic lymphoblastic leukemia
  • ochronic myeloid leukemia

When should you see a doctor?

If you suffer from severe pain in the abdomen, fever, lack of urine output, water retention in the legs, or severe discomfort. The doctor may ask you the following questions:

  • Have you suffered from other illnesses recently?
  • Have you had a fever in the past few weeks?
  • Do you know of any other diseases?
  • Do you take medication regularly? If yes, which?
  • Have you been abroad recently?
  • Have you seen any other symptoms or signs? If yes, which?
  • Is your urine foaming?
  • Do you have to urinate unusually frequently and significantly more than before? Also, at night?
  • Are there known kidney diseases in the family?

Physical examination

  • The doctor will examine whether you have any signs of an increased amount of fluid in the body. Are your legs swollen?
  • Is tapping on the flanks (kidney area) painful?
  • Do you have a fever?
  • Blood pressure is measured.
  • You will be asked to give urine so that it can be examined.
  • Your blood may be drawn to find signs of an infection or kidney problems.

Protein Takeway:
protein in urine

It is advisable to also seek medical help anytime you experience the above signs and symptoms early enough.


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