Classification

Clinical Significance

• Macroscopic haematuria is a strong predictor of serious underlying urological pathology. In one large study, 21% of patients with macroscopic haematuria were found to have malignancy.
• Microscopic haematuria screening in asymptomatic patients has limited value — fewer than 2% of young patients with a positive dipstick test have a serious treatable urinary tract disease.
• Urine dipstick is useful if positive, but insufficient alone to confirm haematuria; myoglobin and free haemoglobin in urine cause false-positive dipstick results.

Common Causes (Non-Glomerular)

1. Urolithiasis (stone disease) — ~95% of patients with acute renal colic have haematuria
2. Malignancy — e.g., bladder cancer (most common presentation is painless haematuria)
3. Infection (UTI, cystitis)

Glomerular vs. Urological Origin

• Glomerular/renal origin is suggested by: proteinuria, RBC casts, raised creatinine, or hypertension → refer to nephrologist
• Epithelial/urological origin → refer to urologist

When to Refer

• Any single episode of symptomatic microscopic haematuria or gross haematuria warrants specialist referral
• Asymptomatic patients: refer only if >3 RBCs/HPF on two of three urinalyses (American Urological Association)
• High-risk groups warranting expedited assessment: smokers, occupational exposure to benzene/aromatic amines, irritative voiding symptoms, recurrent UTIs, pelvic irradiation, analgesic abuse