The term hematuria describes the presence of intact red blood cells in the urine, which are visible upon microscopic examination. The urine may be pink or red and cloudy.
If RBCs have been destroyed, hemoglobin will be present in the urine, known as hemoglobinuria. The urine color will be pink or red but clear rather than cloudy.
The presence of more than five RBCs per microliter of urine is considered clinically significant. For this reason, a chemical test is needed to detect quantities of blood too small to change the color of urine. Microscopic examination differentiates between hematuria and hemoglobinuria if the chemical reagent strip is positive for blood.
