There is occult blood in the urine, not necessarily nephritis, urine occult blood positive in the clinical mainly seen in the following five cases: a. nephritis, there is a part of mild nephritis, the patient’s urine test only showed positive occult blood and urine protein is negative, you can further check the urine microalbumin to confirm. Second, urinary system infection, in the inflammatory state capillary permeability increased, will lead to red blood cell leakage, the formation of urine occult blood positive. Third, hematologic disorders resulting in systemic coagulation dysfunction, or bleeding caused by thrombocytopenia. IV. Interference from female menstruation, or contamination during the retention of urine specimens. V. In about 15% of patients with hematuria, the cause of the hematuria cannot be clearly identified despite multiple tests, which is called benign hematuria, and these patients only need to be reviewed regularly, and no clinical intervention of drugs is required.