Protein in urine

Clinical significance:

In healthy people, small amounts of protein are excreted in the urine (20 – 80 mg/day), whichre undetected by routine methods. The gral limit of normal values is considered to be 100 – 150 mg/day. About 43% are proteins produced in the urogenital system. The most important of these is Tamm-Horsfall protein, a glycoprotein synthesized by the cells of the nephron loop, distal tubulesl and proximal tubulesl. This protein is a majoringredient of renal tubules.

In addition to this, the cellsrs of the genitourinary system produce more than a dozen other proteins that are excreted in the urine. Small-molecule proteins from serum – albumin, immunoglobulins G and A, transport proteins, and others also enter the urine.

The following proteins are also excreted in the urine

Proteinuria is defined as the excretion of more than 150 mg of protein per day. Increased excretion of protein in the urine also occurs in healthy people as the so-called functional proteinuria: after great physical exertion (marching proteinuria, functional proteinuria), with prolonged standing (orthostatic proteinuria), with a sudden change in temperature – cooling or warming (thermal proteinuria), after a strong psychological experience (emotional proteinuria) or as pseudo-pseudo-proteinuria with a significant concentration of urine.

Pseudo-proteinuria

In this type of proteinuria, protein excretion usually does not exceed 1 g/day and quickly returns to normal values. Ralso in the third trimester of pregnancy, protein excretion is slightly increased to 200 – 300 mg/day. Since the concentration of protein in the urine varies depending on the time of day and physical activity for accurate data on the amount of proteinuria should be determined in daily urine.

Pathological proteinuria is divided according to the amount of protein excreted or according to the cause. Quantitative proteinuria includes: negligible (minimal) proteinuria – protein excretion up to 0.5 g/day; mediocre (moderate) proteinuria – 0.5 – 3.5 g/day; massive (significant) proteinuria – more than 3.5 g of protein/day. Amongs causative proteinuria are the following:

• pre-renal proteinuria – in circulatory failure, hypertension, poisoning, fever, acute neurological episodes (inflammation, stroke, epileptic seizure);
• renal proteinuria:
  • glomerular (acute or chronic glomerulonephritis, autoimmune diseases, diabetes, nephrotoxic drugs, infections);
  • glomerulonephritis (acute and chronic pyelonephritis, interstitial kidney diseases, heavy metal salt poisoning, drug – aminoglycosides, cytostatics, anti-bl drugs);
  • mixed glomerulonephritis;
• proteinuria from overload(overload) or leakage(overflow):
• Bence-Jones protein - multiple myeloma, lysozyme in myeloid leukemia, beta2-microglobulin in chronic lymphatic leukemia, cancer, immune diseases, AIDS, og&oacute infections;
• hepatic diseases, hemoglobin-massive intravascular hemolysis, verrucous melanoma, myoglobin-high physical exertion, skeletal muscle inflammation, crush syndromes, post-epileptic seizure, tetanus, myocardial infarction
• extrarenal proteinuria – inflammation of the uretersve, bladder, urethra, prostate gland, lower sectionsve of the genital tract, urolithiasis