Symptom

Blood in Urine: Causes and When It Needs Urgent Investigation

Haematuria — blood in the urine — always warrants evaluation. While UTI is most common, visible haematuria without pain in adults over 45 should be urgently investigated to exclude cancer.

Visible haematuria
Urgent referral indicated (over 45)
Microscopic haematuria
Detected on dipstick only
Cancer cause
Bladder cancer in ~5% of visible haematuria
Most common (young)
UTI, kidney stones, exercise
Urgent ReferralVisible haematuria (blood you can see) in adults over 45 — or over 60 with microscopic haematuria + dysuria/raised WBC — requires 2-week wait urgent urology referral to exclude bladder or kidney cancer.

Causes by Type

TypeCommon CausesKey Feature
Visible (gross) haematuriaBladder cancer, kidney cancer, kidney stones, severe UTIAlways investigate in adults >45
Microscopic haematuria + UTI symptomsCystitis, urethritis, prostatitisTreat UTI; recheck after treatment
Microscopic haematuria, no symptomsIgA nephropathy, thin glomerular basement membrane, exerciseKidney function + protein check
Haematuria + loin painRenal stones, renal tract tumour, pyelonephritisImaging (CT urogram/USS)
Cola-coloured urineGlomerulonephritis (blood + protein), haemolysis, myoglobinuriaUrgent nephrology or A&E assessment
Dipstick Positive — Confirm with MicroscopyA positive dipstick can be caused by haemoglobin or myoglobin (not red cells). Always confirm with urine microscopy to detect actual red blood cells — particularly important before deciding on referral.
Is blood in urine always serious?
Not always. UTI and kidney stones are common and usually benign. However, visible haematuria in adults, particularly without pain (painless haematuria), is a red flag for urological cancer — always investigate urgently.
What is IgA nephropathy?
The most common glomerulonephritis globally — characterised by microscopic haematuria with episodic visible haematuria (often following a throat infection). Caused by IgA deposits in glomeruli. Can slowly progress to CKD.
Can exercise cause blood in urine?
Yes — vigorous exercise (especially running) can cause transient microscopic haematuria. It resolves within 72 hours of rest. If persistent, investigate for underlying cause.
What tests investigate haematuria?
Urine dipstick → microscopy → culture. Upper tract: CT urogram or renal ultrasound. Lower tract: flexible cystoscopy (bladder camera). Blood: eGFR, ACR, urine PCR.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.