Urinary occult blood ± usually means weakly positive urine occult blood, suggesting the presence of a small number of red blood cells in the urine, which may be physiologic or pathologic. There are no red blood cells in normal urine, i.e., occult blood is negative. If the urine occult blood weak positive, need to observe the number of red blood cells under the microscope, if the number of red blood cells per high magnification is less than three, it may not be true hematuria, it may also be the result of test error. If the number of red blood cells is greater than three, belong to the real hematuria, the more common causes are physiological and pathological two. Physiologic causes are common in cases of strenuous exercise, fever, and left renal vein compression, but this is only transient and does not require special treatment. Pathological causes are more common in urinary tract infections, stones, tumors and various nephritis. If the patient occurs urinary occult blood ±, it is recommended to go to the regular hospital in a timely manner to improve the examination to clarify the cause of the disease, under the guidance of the doctor to the targeted treatment or treatment.