Why does bladder cancer cause blood in urine?

The bladder stores urine. A growth on its inner surface can be fragile, and urine passing over it may disturb small blood vessels. Blood may make the urine pink, red or brown, or it may only be found on a urine test. Blood in Urine is a very common presentation of Bladder Cancer, but it also has other possible causes, including infection, stones, kidney conditions, medicines and exercise. The appearance of the urine alone cannot identify the cause.

Arrange a medical assessment for visible blood in the urine, even if it clears or is not painful. The clinician may ask about burning, urgency, clots, pain, smoking and medicines, then test a urine sample. Depending on the findings, assessment can include blood tests, imaging or a camera examination of the bladder. Bring a list of medicines and note when the colour change began and whether it comes and goes.

Seek urgent medical help if you cannot pass urine, are passing clots, have heavy bleeding, severe lower abdominal or side pain, fever with urinary symptoms, or feel faint or very unwell. These signs need prompt assessment because a clot can obstruct urine flow and infection or bleeding may need treatment.

Ask what your urine test shows, whether a bladder examination or imaging is appropriate, and what changes should prompt urgent care. If you take blood-thinning medicine, ask whether it affects the plan; do not stop prescribed medicine unless the clinician tells you to.