Hematuria is defined as the presence of blood in the urine. It may be further classified as gross hematuria (enough blood to make the urine look abnormal to the naked eye) or microscopic hematuria (blood can be detected only through chemical testing or microscopic examination). Gross hematuria may appear as a brown or cola-colored urine, which suggests a renal (kidney) origin of bleeding. Pink or red urine is associated with lower urinary tract blood loss. Bleeding from the bladder or urethra may also cause tiny blood clots in a urine specimen.
An inherited structural abnormality of the kidneys in which small numbers of red blood cells are found in the urine. On biopsy the glomeruli of affected patients are found to have thin basement membranes. The condition is not associated with progressive kidney failure or other progressive renal diseases.