Blood in Urine (Haematuria) — Causes, Diagnosis & When to Worry — Symptoms, Causes & Treatment | MyMedicPlus

Haematuria refers to the presence of red blood cells in the urine. Gross (visible) haematuria is blood visible to the naked eye — the urine appears pink, red, or brown. Microscopic haematuria is detectable only by urine dipstick or microscopy. Any episode of unexplained visible haematuria in an adult requires urgent investigation regardless of age, as bladder cancer and other serious conditions must be excluded. Microscopic haematuria also warrants investigation in patients over 40 or with risk factors. Up to 2.5% of the adult population experience an episode of visible haematuria annually. Haematuria can originate from anywhere along the urinary tract — kidneys, ureters, bladder, prostate, or urethra — and may signify benign conditions such as UTI or kidney stones, or serious malignancies. Pseudohaematuria (red discolouration from beetroot, rifampicin, or myoglobinuria) must be distinguished by urine microscopy confirming true red blood cells. All unexplained haematuria warrants prompt investigation, as a single episode may be the only presentation of an otherwise asymptomatic urothelial tumour.

Urological causes (most common): bladder cancer, bladder stones, urinary tract infection (UTI), kidney stones (nephrolithiasis), kidney cancer (renal cell carcinoma), prostate cancer or benign prostatic hyperplasia (BPH), trauma, and urethritis. Renal/nephrological causes: IgA nephropathy (Berger's disease — most common glomerulonephritis globally), other glomerulonephritides, thin basement membrane disease, Alport syndrome, and vasculitis. Other causes: anticoagulant medications (warfarin, DOACs — associated with higher bleeding risk), vigorous exercise (runner's haematuria — typically resolves within 48 hours), endometriosis, and vascular malformations. Transitional cell carcinoma of the bladder is the most important cause to exclude in adults over 40 with unexplained visible haematuria — occupational exposures to aromatic amines (dye, rubber, leather industries) increase bladder cancer risk 4-6-fold. Schistosomiasis (Schistosoma haematobium) is a major cause of haematuria and bladder cancer in sub-Saharan Africa and the Middle East.

Visible haematuria: urine appears pink, red, brown, or tea-coloured. It may be painless (bladder cancer, renal tumour) or painful (kidney stones — severe loin-to-groin colicky pain; UTI — dysuria, frequency, urgency). Blood at the start of urination suggests a urethral or prostate source; terminal haematuria (at the end) suggests a bladder neck or trigone source. Total haematuria throughout urination suggests bladder or upper tract origin. Haematuria with loin pain, proteinuria, and hypertension suggests a renal/glomerular cause. Significant haematuria causing clot formation can cause urinary retention. Haematuria with systemic features — weight loss, night sweats, or bone pain — raises concern for malignancy with metastatic spread and warrants urgent comprehensive investigation rather than a reassurance-only assessment. Painless haematuria in a smoker or ex-smoker over 50 has a particularly high probability of underlying urothelial malignancy.

Initial assessment: urine dipstick (highly sensitive for haematuria); urine microscopy confirms red blood cells and identifies casts (dysmorphic RBCs and RBC casts suggest glomerular pathology); midstream urine (MSU) culture excludes infection. All adults with unexplained visible haematuria: urgent flexible cystoscopy (direct bladder visualisation within 2 weeks) plus CT urogram (imaging kidneys, ureters, and bladder). Urine cytology for high-grade urothelial cells. Renal biopsy for suspected glomerulonephritis. PSA in males over 50 to screen for prostate cancer. Blood tests: creatinine, eGFR, FBC, coagulation screen, and autoimmune profile for suspected glomerulonephritis. Urine NMP22 (nuclear matrix protein 22) and BTA (bladder tumour antigen) tests supplement cytology for urothelial cancer detection; however, flexible cystoscopy remains the definitive diagnostic standard as neither test replaces direct bladder visualisation.

Treatment is directed at the underlying cause: UTI — antibiotic course; kidney stones — analgesia (NSAIDs, opioids), alpha-blockers (tamsulosin) to facilitate passage, lithotripsy, or ureteroscopy for larger stones; bladder cancer — TURBT, intravesical therapy, or cystectomy; renal cell carcinoma — partial or radical nephrectomy, targeted therapy, immunotherapy; glomerulonephritis — corticosteroids, immunosuppressants, ACE inhibitors for proteinuria and hypertension; BPH-related haematuria — 5-alpha reductase inhibitors (finasteride). Continuous bladder irrigation or cystoscopic fulguration for persistent haematuria. Anticoagulant reversal if medication-induced. Bladder instillation of BCG (Bacillus Calmette-Guérin) immunotherapy after TURBT for high-risk non-muscle-invasive bladder cancer reduces recurrence by 40-50% and decreases progression to muscle-invasive disease. Pembrolizumab is licensed for BCG-unresponsive non-muscle-invasive high-grade bladder cancer. For upper tract urothelial cancer (renal pelvis, ureter), radical nephroureterectomy is the standard curative procedure. Erdafitinib (FGFR inhibitor) is approved for FGFR-altered metastatic bladder cancer after platinum-based chemotherapy failure.

Missed or delayed investigation of visible haematuria is a serious concern — up to 22% of patients with visible haematuria have bladder cancer or upper tract urothelial cancer, and delayed diagnosis allows tumour progression to muscle-invasive or metastatic disease where treatment outcomes are significantly worse. Clot retention from heavy haematuria causes painful urinary retention requiring emergency catheterisation. Significant blood loss can cause anaemia. Untreated glomerulonephritis may progress to chronic kidney disease and renal failure. Any unexplained haematuria, however brief, requires prompt investigation.

Smoking cessation is the most important prevention for bladder and kidney cancer (major haematuria causes). Stay well hydrated — 1.5-2 litres of water daily reduces kidney stone formation and concentrates carcinogens in urine, reducing bladder cancer risk. Maintain healthy blood pressure to prevent glomerular damage. Use NSAIDs only when necessary, as prolonged use causes renal damage and papillary necrosis (with haematuria). Protect kidneys from trauma during contact sports. If taking anticoagulants and experiencing haematuria, do not stop medication independently — contact your doctor for urgent assessment, as haematuria in anticoagulated patients still warrants full urological investigation.

Any episode of visible blood in urine in an adult requires prompt medical review — even if it resolves spontaneously. See a GP within 24-48 hours or attend urgent care for all unexplained visible haematuria regardless of age. Attend A&E immediately for: heavy haematuria with blood clots, inability to pass urine (clot retention), or visible haematuria with loin pain suggesting renal colic or obstruction. Do not be reassured by a concurrent UTI — UTI and bladder cancer can coexist, and investigation must continue after antibiotic treatment. Microscopic haematuria in adults over 40 or with risk factors (smoking history, occupational chemical exposure, recurrent UTI, previous pelvic irradiation) also warrants urological investigation with cystoscopy and CT urogram.