Blood in urine (hematuria)

Blood in the urine (hematuria) means red blood cells are present in the urine. It can be visible (the urine looks pink, red or brown — 'visible' or 'gross' hematuria) or invisible, detected only when a urine test is done for another reason ('non-visible' or 'microscopic' hematuria). Either way, it should not be ignored, because the causes range widely and include some that need prompt attention. Common and often less serious causes include a urinary tract infection, a kidney or bladder stone (typically with pain), an enlarged prostate in men, and vigorous exercise. Kidney conditions (such as glomerulonephritis, sometimes signalled by protein in the urine too) are another group. Critically, blood in the urine — particularly when it is visible and painless — can be the first sign of bladder or kidney cancer, which is why it is taken seriously and investigated, especially in older adults and smokers. (Some things stain urine red without being blood, such as beetroot or certain medications, which testing distinguishes.) Because the list includes both minor and serious causes, the purpose of assessment is to find the reason.

• Urinary tract infection — a common cause, often with burning and frequency.
• Kidney or bladder stones — usually with pain (colic or on passing urine).
• Enlarged prostate (men).
• Vigorous exercise — a temporary, harmless cause.
• Kidney disease (glomerulonephritis) — often with protein in the urine.
• Bladder or kidney cancer — especially visible, painless blood, in older adults or smokers; the key reason to investigate.
• Blood-thinning medication — can make bleeding from any of the above more apparent. Red urine from beetroot or some medicines is not blood — testing tells them apart.

Blood in the urine is confirmed and characterised with urine tests: a dipstick and microscopy confirm true blood and look for signs of infection or protein, and a urine culture checks for infection. Blood tests support the assessment: kidney function (creatinine, eGFR) and, where a kidney cause is suspected, protein/albumin in the urine (microalbumin) and other kidney markers. Because cancer is part of the differential, visible or persistent non-visible blood usually prompts imaging of the urinary tract and, often, a look inside the bladder with a camera (cystoscopy), arranged by a specialist. Mediora.AI can surface a kidney-function or protein pattern that points toward a kidney cause, but blood in the urine — especially visible or painless — needs proper investigation by your doctor, not a blood test alone.