Urinalysis occult blood 3+ often suggests the presence of microscopic hematuria, which is divided into physiological and pathological causes. Physiological includes strenuous exercise, female menstrual blood pollution during menstruation, etc. Pathological includes stones, urinary tract infection. Physiological: after strenuous exercise, female menstrual blood contamination of urine, there may be occult blood in the urine, it is recommended to rest, review after menstruation, generally no need for treatment. Pathological: stones lead to tissue destruction and erosion caused by bleeding, the formation of hematuria; urinary tract infection so that the mucosa of the urinary tract inflammatory reaction, edema, bruising, destruction of small blood vessels, the emergence of occult blood in the urine. In addition nephritis, urinary tract tumors, etc., may also appear such test results, the specific disease need to go to the hospital for a more comprehensive examination. It is recommended that patients with urinary occult blood 3+ are advised to go to the hospital in time, to clarify the cause of the disease under the guidance of professional physicians, and timely treatment.