Three + in routine urine occult blood refers to blood in the urine, which is clinically called hematuria. The common causes of hematuria are: i. Infectious diseases, such as acute cystitis and acute pyelonephritis, which are mostly seen in female patients. Second, stones in the urinary tract, especially acute obstruction of ureteral stones, after extracorporeal lithotripsy treatment, various surgical methods, in vivo lithotripsy or lithotripsy, can cause varying degrees of hematuria. Urological tumors, mainly referring to metastatic cell carcinoma of the renal pelvis, ureter and bladder, mostly cause intermittent painless hematuria. Internal diseases, such as coagulation dysfunction, blood disorders, long-term oral anticoagulant drugs, and side effects of certain chemotherapy drugs, etc. V. Sports hematuria. Sixth, there are also some hematuria with unknown causes, which need to be further investigated.