Quick answer

What could blood in urine mean?

Blood in urine (haematuria) may appear pink, red or brown, or be found only on a urine test. Causes range from urine infections and kidney stones to — rarely — bladder or kidney cancer. See a GP the same day for visible blood in urine, especially if you are over 45 or smoke — urgent assessment rules out serious causes.

Blood in urine always needs checking

Blood in urine — haematuria — means red blood cells are present. It may be visible (the urine looks pink, red or brown) or non-visible (found only on a dipstick or laboratory test). Even a single episode of visible blood, or blood that appears once and stops, warrants same-day GP assessment because serious conditions — including bladder and kidney cancer — can be the cause.

What you might notice with blood in urine

You might notice:

  • your urine looks pink, red or tea-coloured
  • there are blood clots in your urine (this is less common)
  • you see no change at all, and blood is found on a routine urine test at the GP

Blood at the start of urination may suggest a urethral or prostate source, while blood throughout the stream may indicate a bladder or kidney origin. Blood at the end may suggest a problem at the bladder neck or prostate. A GP interprets the pattern alongside test results.

Common causes of blood in urine

A urinary tract infection (UTI) causes burning when passing urine and needing to go frequently, sometimes with blood. UTIs are more common in women.

Kidney stones cause severe pain in the back or side together with blood in the urine. See our kidney stones guide for more detail.

Exercise-induced haematuria can follow long-distance running or intense exercise and causes temporary blood in the urine. It is a diagnosis of exclusion, meaning other causes must be ruled out first.

An enlarged prostate in men can cause blood alongside urinary symptoms, typically over the age of 50. Kidney inflammation (glomerulonephritis) may cause blood in the urine together with swelling and high blood pressure.

Some medicines, particularly anticoagulants (blood thinners), increase the risk of bleeding, but they do not explain blood in the urine without another underlying cause.

Bladder or kidney cancer often causes painless visible blood. It is more common in smokers and in people over 45, and early diagnosis improves treatment success.

When blood in urine is an emergency

Call 999 if:

  • you cannot pass urine at all (retention)
  • you have severe pain with blood and feel very unwell
  • you have fever, rigors and blood in your urine with flank pain, which may indicate a kidney infection

See a GP the same day for any visible blood — even without pain, and even if it happens only once.

What assessment for blood in urine involves

A GP will usually arrange several tests. Urine tests check for infection, blood and protein, and blood tests check kidney function.

Imaging, such as an ultrasound or CT scan, examines the kidneys and urinary tract. A cystoscopy — a camera examination of the bladder — may also be recommended, especially if you are over 45, smoke, or have persistent blood.

The assessment is structured to find treatable causes quickly.

Do not ignore blood in urine

Many people delay seeking help because the blood appeared once and then stopped, or because there is no pain. Painless visible haematuria is a classic presentation of bladder cancer, and early detection saves lives. Same-day GP assessment is the right response every time.

Blood in urine and anticoagulants

If you take warfarin, apixaban or a similar medicine and notice blood in your urine, see a GP the same day. Do not stop your anticoagulant without medical advice — but the bleeding still needs investigation.

If you also have burning when urinating and need to go frequently, a UTI may be the cause — but this still needs confirmation. Flank pain with blood suggests kidney stones. A GP connects your symptoms to the right tests.

Common questions about blood in urine

What does blood in urine look like?
Urine may be pink, red, tea-coloured or brown. Sometimes blood is invisible and is found only when a GP or nurse tests the urine (non-visible haematuria). Even a single episode of visible blood needs assessment.
What causes blood in urine?
Common causes include urinary tract infections, kidney stones, an enlarged prostate in men, exercise-induced haematuria, and kidney inflammation. Less common causes include bladder or kidney cancer, blood clotting disorders, and certain medicines. A GP arranges tests to find the cause.
Can blood in urine be harmless?
Sometimes — vigorous exercise or minor infection can cause temporary blood. But because serious conditions including cancer can cause blood in urine, a GP should assess every episode to rule out important causes.
What tests will a GP do for blood in urine?
A GP will usually arrange urine tests, blood tests, and often referral for imaging such as an ultrasound or CT scan of the kidneys and bladder. Men may have a prostate examination, and cystoscopy (a camera into the bladder) may be recommended, especially over 45 or if tests are abnormal.
Is blood in urine a sign of cancer?
Bladder and kidney cancer can cause blood in urine — often without pain. It is not the most common cause, but early detection improves outcomes. This is why same-day GP assessment matters, especially for smokers and people over 45.

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