The difference between visual hematuria and microscopic hematuria is the difference in the amount of bleeding. If the amount of bleeding is high, the number of red blood cells in the urine is high, which can manifest as red urine. Abnormal urine can be detected by eye observation, such as reddish color with wash water-like color or appearing light red or pink in color, can be called carnal hematuria, but microscopic hematuria indicates that the blood is relatively mild and the number of red blood cells in the urine is over the limit, but there is no abnormal change in the color of the urine when observed with the naked eye. There is no difference in the appearance of the urine from normal urine, but when the number of red blood cells is greater than 3 per high magnification field through microscopic examination, it is called microscopic hematuria, and all are changes of urinary bleeding, but the cause is unknown. The hematuria found with the naked eye is often caused by more bleeding, while microscopic hematuria is often caused by less bleeding and can only be observed with the microscope, not with the naked eye.