Blood in urine

When red blood cells are detected in the urine — but the urine doesn't appear red from blood — this is called "microscopic hematuria." Blood in urine can be caused by many conditions, including:

• Urinary tract infection (cystitis)
• Bladder or kidney stone
• Noncancerous or cancerous enlargement of the prostate in men
• Bladder or kidney cancer
• Kidney disease, such as nephritis
• Medications such as warfarin, aspirin, ibuprofen and naproxen

To try to determine the cause of blood in urine, your doctor may recommend additional tests, such as:

• Urine tests (urinalysis)
• Blood tests
• Kidney- and bladder-imaging studies
• Cystoscopy, a procedure in which a narrow tube is inserted through your urethra and into your bladder, which allows your doctor to visually inspect your urethra and bladder

Sometimes the cause can't be determined. In such cases, your doctor may simply monitor the condition to see if it persists. If blood is visible in your urine (gross hematuria), consult your doctor.