Kidney cancer and blood in urine: what to know

Blood may be visible, making urine look pink, red or brown, or it may only be found by a urine test. Kidney cancer can cause haematuria because a tumour may affect delicate blood vessels or the urine-collecting system. Many other conditions can do this too, including a urinary tract infection, kidney stones, kidney infection, bladder cancer, prostate conditions and prostatitis. Sickle cell disease can also affect the urinary system. The appearance of urine alone cannot identify the cause, and blood may occur without pain.

A clinician may ask about urinary symptoms, pain, fever, medicines and previous episodes. Assessment can include urine testing, blood tests and imaging, with further tests arranged when needed.

Arrange a medical appointment for any unexplained blood in urine, even if it happens once or disappears. Note when it began, whether it was visible, whether clots or pain occurred, and any change in urinary frequency or flow. Take a list of medicines and supplements, especially medicines that affect bleeding.

Do not assume that clear urine means the cause has resolved. A clinician may repeat urine testing after treating an infection or may arrange imaging and specialist review if blood persists or has no clear explanation. Avoid taking leftover antibiotics or changing prescribed medicines without advice.

Seek urgent medical help if blood in urine is heavy, clots stop urine from passing, or bleeding comes with severe side or back pain, fever, vomiting, faintness or marked weakness. These features can signal blockage, infection, bleeding or another problem needing prompt treatment.

Call emergency services for collapse, confusion, severe difficulty breathing or chest pain. Otherwise, contact a clinician promptly rather than waiting for another episode.

Ask what tests are appropriate, whether the pattern suggests infection, stones or another urinary cause, and whether imaging or urology review is needed. Ask when results will be available and what changes should prompt earlier contact.