Hematuria, i.e. the excretion of red blood cells (erythrocytes) in the urine, can have many causes. During the period or during intense sports, it is quite normal that blood is in the urine. However, blood also occurs in the urine in many diseases.
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Therefore, careful clarification of the cause is absolutely necessary. In particular, hematuria may indicate a urinary tract infection, kidney disease, kidney stones or tumors (e.g. bladder cancer). Injuries to the kidneys, bladder or urinary tract can also lead to hematuria.
Further information
A so-called macrohematuria is visible to the naked eye. From about 0.5 – 1 ml of blood / liter of urine results in a visible red coloration of the urine. This red coloration can range from flesh-colored, pink or light red to strong red.
A so-called microhematuria (up to 0.5 – 1 ml of blood/l urine) can only be determined by examining the urine using test strips or under a microscope.
Since the hematurias occur in many diseases even before painful symptoms develop, they are a relatively good early indicator.
The test strip for blood in the urine may also indicate myoglobinuria. Myoglobin is responsible for the transport of oxygen within muscle cells. It occurs only in the skeletal and heart muscle cells of mammals. Myoglobinuria is caused by the increased breakdown of muscle cells in the context of various diseases or in rhabdomyolysis, a dissolution of cross-striped muscle cells. This can occur after intensive training.
Hemoglobinuria, i.e. free hemoglobin (red blood dye) in the urine, can also be diagnosed by means of test strips. It occurs when more red blood cells disintegrate, causing the hemoglobin to leak out of the erythrocytes and finally excreted via the kidneys. This can be caused by various toxins or malaria.
A reddish discoloration of the urine is not always an indication of a disease. Also some strongly colouring foods, such as beetroot, can discolor the urine. This discoloration usually disappears after 2 to 3 times urination.
Sources
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- Schuetz, E. et al. (1985): Effect of diuresis on urinary erythrocyte morphology in glomerulonephritis. Klin Wochenschr, 63, 575
- Lahnsteiner, E. et al. (2004): Harnanalyse – praktisch zusammengefasst, 2. Auflage
- Fogazzi, G. B. et al. (1996): Microscopic hematuria diagnosis and management. Nephron, 72, 125
- Fogazzi, G. B. (1996): The erythrocyte cast. Nephrol Dial Transplant, 11, 1649.
- Hebert, L. A. et al. (1995): Relationship between appearance of urinary red blood cell/ white blood cell casts and the onset of renal relapse in systemic lupus erythematosus. At J Kidney Dis, 26, 432.
- Rogers, P.W. et al. (1973): Familial benign essential hematuria. Arch Intern Med, 131, 257
- Reid, R.I. et al. (1987): Haematuria following marathon run, source and significance. bBr J Urol, 133
- Nonnenmacher, Dr. (2018): Blood in the urine, URL: https://medlexi.de/Blut_im_Urin
