Urinary occult blood 3 + normal renal function, may be physiological factors, acute injury, urinary tract infection disease, urinary tract stones, urinary tract tumors and other factors. 1. Physiological factors: during urination, menstrual blood enters the urine and contaminates the urine, leading to strong positive urinary occult blood, which can be recovered independently after the physiological cycle and does not require special treatment. 2. Acute injury: such as foreign body stimulation or external blows, resulting in localized damage to the urethra, a small amount of blood into the urine, will lead to strong positive urinary occult blood, may also be accompanied by mild pain and swelling and other symptoms. 3. Urinary tract infections: for example, urethritis or cystitis, after the infection is aggravated, resulting in damage to the bladder or urethra mucosa, which will cause hematuria, usually accompanied by frequent urination, urinary urgency, urinary pain and other symptoms. 4. Urinary stones: for example, bladder stones, in the position change or strenuous exercise, the stone movement, resulting in bladder damage, will cause urinary occult blood strong positive, may also be accompanied by urinary difficulty, urinary pain and other symptoms. 5. Urinary tract tumor: for example, bladder tumor, tumor local tissue necrosis and bleeding, there will be microscopic hematuria or hematuria visible to the naked eye, which may be accompanied by lower abdominal distension, dysuria and other symptoms. When urinary occult blood 3+ kidney function is normal, it is recommended to consult a doctor for examination as soon as possible, and follow the doctor’s instructions for treatment if necessary, to avoid aggravation of the lesion.