If there are stones in the urinary system, it can cause occult blood with two plus signs, usually accompanied by obvious pain in the lower back and abdomen, especially in the area where the stones are located, and need to be treated with extracorporeal shock wave lithotripsy. 2. When urinary tract infection occurs, occult blood may also be positive, and further urine culture is needed. If the presence of tumor is confirmed, further cystoscopy or biopsy will be required, and surgery will be considered at a later stage.