Blood in the urine

Two forms of haematuria, with different risks

• Visible haematuria. The urine looks red, pink or tea-coloured. This is the one that frightens people and brings them in, and rightly so: it carries the highest risk. A single episode, even if it happened once and months ago, places the patient in the high-risk group.
• Microscopic haematuria. It cannot be seen; it shows up on a urine test, often requested for another reason. It is defined as three or more red blood cells per high-power field on a properly collected sample. It is far more common and its risk depends on who the patient is.

Risk groups and the probability of cancer

For years everyone underwent the same tests. Since 2020, with an update in 2025, the American Urological Association risk classification makes it possible to match the intensity of the evaluation to each person's actual risk.

The highest applicable category governs: meeting a single criterion in a group is enough to belong to it.

Risk factors for urinary cancer

These are the elements that move a patient into a higher category, and each one deserves to be gone through in consultation:

• Smoking. By far the most important: around half of all bladder cancers are attributed to it. The risk persists for years after stopping.
• Age and male sex.
• Occupational exposure to aromatic amines, dyes and hydrocarbons: rubber, leather and textile industries, paints, petrochemicals, printing and hairdressing. This is rarely asked about, and it changes the classification.
• Previous pelvic radiotherapy, for example for prostate cancer.
• Previous chemotherapy with cyclophosphamide or ifosfamide.
• Recurrent urinary infections or long-term catheter use.
• Prolonged analgesic use and exposure to aristolochic acid, present in some herbal remedies.
• Family history of urothelial cancer or Lynch syndrome.
• Any previous episode of visible haematuria.

What can cause it

Most cases of haematuria are not cancer. The commonest causes are benign:

• Urinary infection and prostatitis.
• Stones in the kidney or ureter.
• Benign prostatic enlargement, particularly where the prostate is heavily vascularised.
• Intense exercise, trauma, recent procedures.
• Kidney disease of non-urological origin, usually accompanied by protein in the urine and impaired kidney function.
• Tumours of the bladder, kidney, upper urinary tract or prostate.

What the evaluation involves

• Urinalysis with microscopic examination of the sediment, and a urine culture where infection is suspected.
• Cystoscopy. Direct inspection of the inside of the bladder and urethra with a flexible instrument, in the office under local anaesthetic. It is the only test that sees inside the bladder: no scan replaces it, because flat tumours —carcinoma in situ— cannot be seen on CT.
• Imaging of the upper urinary tract. Renal ultrasound in intermediate risk; CT urography —a contrast scan with specific phases to visualise the urinary tract— in high risk.
• Urine cytology or urinary markers in selected cases. The 2025 update allows for these to refine the decision in intermediate-risk patients who would rather avoid cystoscopy, but they do not replace cystoscopy in high-risk patients.

Why this belongs with a urologic oncologist

Any urologist can perform a cystoscopy, and many doctors can order a urine test. It is not a question of who is able to: it is a question of what happens next.

Evaluating haematuria is, fundamentally, a search for cancer. And when something turns up, the path branches into precisely the procedures a urologic oncologist performs day in, day out:

• A bladder tumour requires transurethral resection, correct staging and a decision on whether it needs intravesical treatment, radical cystectomy or chemotherapy first.
• A renal mass calls for correct interpretation of the CT and a choice between surveillance, partial or radical nephrectomy, with the aim of preserving kidney whenever possible.
• An upper tract tumour leads to nephroureterectomy with management of the bladder cuff.
• A bleeding prostate may be benign or may conceal a tumour, and the two must be told apart.

When to seek help without waiting

• Any episode of visibly bloody urine, even a single one that has not recurred.
• Blood accompanied by clots, or difficulty passing urine because of obstruction.
• Painless haematuria. The absence of discomfort is not reassuring: bleeding from a tumour is typically painless.
• Haematuria on a routine test if you are a smoker, over 50, or have had occupational exposure.
• Blood that appears after a course of antibiotics that was supposed to have cleared an infection.