Hematuria or haematuria is defined as the occurrence of blood or red blood cells in the urine. The word hematuria is derived from Greek haima (αἷμα) "blood" and ouron (οὖρον) "urine". Hematuria can be visible to the naked eye (termed "gross hematuria") and may appear red or brown (sometimes referred to as tea-colored), or it can be microscopic (i.e. not visible to the eye but detected with a microscope or laboratory test). The origin of the blood that enters and mixes with the urine can arise from any anatomical site within the urinary system, including the kidney, ureter, urinary bladder, and urethra, and in men, the prostate. Common causes of hematuria include urinary tract infection (UTI), kidney stones, viral illness, trauma, bladder cancer, and exercise. The underlying causes of hematuria can be divided into glomerular and non-glomerular causes, referring to the involvement of the glomerulus of the kidney. Notably, not all red urine is hematuria. Other substances such as certain medications and foods (e.g. blackberries, beets, food dyes) can cause urine to appear red. Menstruation in women may also cause the appearance of hematuria and may result in a positive urine dipstick test for hematuria. Additionally, a urine dipstick test may be falsely positive for hematuria due to other substances in the urine such as myoglobin during rhabdomyolysis. A positive urine dipstick test should be confirmed with microscopy, where hematuria is defined by three of more red blood cells per high power field. When hematuria is detected, a thorough history and physical examination with appropriate further evaluation (e.g. laboratory testing) can help determine the underlying cause.