What is haematuria?
Haematuria means red blood cells are present in the urine. It may be visible, where the urine looks pink, red, tea-coloured or contains clots, or microscopic, where blood is detected on urine testing even though the urine looks normal.
These two situations are not identical. Visible haematuria generally deserves more immediate attention, while microscopic haematuria is evaluated according to persistence, age, risk factors and the likelihood of significant urinary tract disease.
What can cause blood in the urine?
Other causes include kidney disease, trauma, recent urinary procedures and bleeding influenced by anticoagulant or antiplatelet medication. Blood-thinning medication may make bleeding more apparent, but it should not automatically be assumed to be the sole explanation.
Why is painless visible blood important?
Pain is not required for haematuria to be significant. Bladder cancer classically may present with painless visible blood in the urine. This does not mean every painless episode is cancer, but it is a reason to investigate rather than wait for recurrence.
When is blood in urine urgent?
Seek prompt or emergency assessment if there is heavy ongoing bleeding, large clots, inability to pass urine, fever with suspected urinary obstruction, severe flank pain, marked weakness, dizziness or the patient is acutely unwell.
Clot retention can block the bladder outlet and may require urgent catheter drainage and bladder irrigation. Infection behind an obstructed urinary tract can also become serious quickly.
What does the evaluation usually involve?
The exact work-up depends on whether the blood is visible or microscopic and on the patient's age, smoking history, urinary symptoms, kidney function and other risk factors.
- History: visible versus microscopic blood, pain, clots, urinary symptoms, infection, stone history, smoking, medicines and previous urinary disease.
- Urinalysis and urine culture: to confirm blood and look for infection or other abnormalities.
- Blood tests: kidney function and other tests when clinically relevant.
- Imaging: ultrasound or CT urography may be used depending on the risk profile and clinical question.
- Cystoscopy: direct inspection of the bladder and urethra, particularly when bladder pathology needs to be excluded.
- Urine cytology: sometimes used as an adjunct, especially when high-grade urothelial cancer is a concern.
Why can cystoscopy be necessary if the scan is normal?
Imaging and cystoscopy answer different questions. A CT or ultrasound can assess the kidneys, ureters and bladder from the outside, but small bladder tumours or flat mucosal abnormalities may not be reliably excluded by imaging alone.
Current European guidance states that cystoscopy remains necessary for diagnosing bladder cancer when symptoms are suggestive; urine cytology and urinary markers do not replace direct visual inspection.
What is the role of CT urography?
CT urography provides detailed imaging of the kidneys, ureters and bladder and is particularly useful when the upper urinary tract needs careful evaluation. It can identify renal masses, urinary tract stones, filling defects and obstruction.
Not every patient with microscopic haematuria needs the same imaging. Modern guidelines use a risk-based approach so that low-risk patients are not exposed unnecessarily to radiation or contrast while higher-risk patients receive appropriate upper-tract evaluation.
What if blood is found only on a urine test?
Microscopic haematuria is common and does not always mean serious disease. The first step is to confirm that red blood cells are truly present and consider obvious temporary causes such as infection or recent strenuous activity.
If microscopic haematuria persists, evaluation is based on the individual's risk profile. The 2025 AUA/SUFU guideline uses risk categories to guide whether repeat urine testing, renal ultrasound, cystoscopy or more detailed imaging is appropriate.
Can a urinary infection explain the blood?
Yes, but the diagnosis should fit the clinical picture. If blood is attributed to infection, it is important to confirm that the haematuria resolves after the infection has been appropriately treated, particularly in patients with risk factors for urinary tract malignancy.
Can kidney stones cause blood without pain?
Yes. Stones can cause microscopic or visible haematuria even when there is little or no pain. However, the presence of a stone does not always prove it is the only source of bleeding, especially in an older patient or someone with risk factors for urothelial cancer.
Does being on a blood thinner change the need for evaluation?
Anticoagulants and antiplatelet drugs can make bleeding more obvious, but they do not exclude an underlying urinary tract cause. The medication history is important, but haematuria still needs to be interpreted on its own clinical merits.
What should you bring to a haematuria consultation?
- Urine reports and urine culture results
- Ultrasound, CT or MRI reports and images if available
- Details of any previous kidney stones or urinary procedures
- List of blood thinners and other regular medicines
- Smoking history
- Any previous cystoscopy or bladder tumour records
- A note of whether the bleeding was painful, painless, with clots, and whether it has happened more than once
Is blood in urine always cancer?
No. Infection, stones, prostate disease and kidney conditions are common causes. Cancer is one important possibility that should be excluded when the pattern or risk profile warrants it.
Should painless blood in urine be investigated?
Yes. Painless visible haematuria is an important warning symptom even when it happens only once.
If my ultrasound is normal, do I still need cystoscopy?
Possibly. Ultrasound and cystoscopy examine the urinary tract in different ways. A normal scan does not reliably exclude all bladder lesions.
Can stones cause blood in urine without pain?
Yes. Stones can bleed without causing classic renal colic, although other causes may still need consideration.
Can blood thinners cause haematuria?
They can contribute to bleeding, but their use does not automatically remove the need to look for an underlying urinary tract cause.
Clinical references
This page is informed by the European Association of Urology guidance on bladder cancer diagnosis and the AUA/SUFU Microhematuria Guideline. Guidelines support clinical decision-making but do not replace individual assessment.