Occult blood

Urine occult blood refers to the presence of hemoglobin and myoglobin in the urine, not red blood cells; under normal circumstances, hemoglobin in plasma is combined with globin and has a large molecular weight, which cannot be filtered from the glomerular filtration membrane without hemoglobinuria. The clinical cause of hemoglobinuria is mainly intravascular hemolysis, that is, a large number of red blood cells in the blood vessel are destroyed and free hemoglobin is released. Excessive free hemoglobin exceeds the binding capacity of globin, and hemoglobinuria is excreted from the kidney. In severe cases, urine Sauce color. The second is hemolysis in the urinary tract, that is, there is red blood cells when urine is stored in the bladder, but it is positive for occult blood due to the release of hemoglobin because the urine specific gravity is too low or the alkaline is destroyed. Myoglobinuria is caused by the destruction of muscle tissue from various causes (degeneration, inflammation, extensive trauma, and metabolic disorders) and is excreted from the urine. Myoglobin has a small molecular weight and can be filtered from the glomerular filtration membrane.