Hematuria – as the name implies – is blood in the urine. Blood is not visible to the naked eye in normal urine, and it is normal to see 0-2 red blood cells per field of view under a high-powered microscope. If the urine is seen to be light red or wash water-like when you urinate, this indicates that there may be hematuria. Most hematuria is caused by diseases of the urinary system, accounting for 98%, and only 2% is caused by systemic or adjacent organ lesions of the urinary system. The most common causes of hematuria are urinary stones, tumors, infections, tuberculosis, injuries, polyps, etc.