Blood in Urine

Bright red blood in the urine causes instant alarm in a patient, and usually generates an emergency appointment or an out-of hours call. Blood may also be picked up by dipstick testing or MSU during the assessment of some other problem or in a routine medical. This is often less frightening even when disclosed to the patient, but should prompt full investigation.

Published: 2nd August 2022 | Updated: 6th September 2022

Differential diagnosis

Common Diagnoses

  • UTI
  • Bladder Tumour
  • Renal/Ureteric Stones
  • Urethritis
  • Prostatic Hypertrophy/Carcinoma of Prostate

Occasional Diagnoses

  • Jogging and Hard Exercise
  • Renal Carcinoma
  • Chronic Interstitial Cystitis
  • Anticoagulant Therapy
  • Nephritis/Glomerulonephritis

Rare Diagnoses

  • Renal Tuberculosis
  • Polycystic Kidney Disease
  • Blood Dyscrasias: Thrombocytopenia, Haemophilia, Sickle-Cell Disease
  • Infective Endocarditis
  • Schistosomiasis (Common Abroad)
  • Trauma
  • Ketamine-Associated Ulcerative Cystitis

Ready reckoner

Key distinguishing features of the most common diagnoses

UTIBladder TumourStonesUrethritisProstate
Frank BloodPossiblePossiblePossibleNoPossible
Urethral DischargeNoNoNoYesNo
Poor Urinary StreamNoPossiblePossibleNoYes
Loin PainPossibleNoPossibleNoNo

Possible investigations

Likely: Urinalysis, MSU, FBC, U&E, ACR/PCR.

Possible: PSA, ultrasound, plain abdominal X-ray, cystoscopy.

Small Print: Urethral swab, CT scan, urine cytology, renal biopsy, angiography.

  • Urinalysis: Pus cells and nitrite in UTI. Pus cells alone in urethritis, TB and bladder tumour. Presence of protein suggests renal disease.
  • Urine microscopy and culture to establish pathogen in infection. May show casts in renal disease.
  • FBC and U&E help establish basic renal function and any associated anaemia or leucocytosis; consider PSA – usually elevated in prostatic carcinoma.
  • ACR/PCR: To quantify any proteinuria.
  • Urethral swabs if urethritis (best done at GUM clinic).
  • If painless haematuria, ultrasound may show renal tumour or polycystic kidneys; CT may be more useful.
  • Specialist investigations include renal imaging, cystoscopy, urinary cytology, renal biopsy and angiography.

Top Tips

  • Microscopic haematuria in an asymptomatic menstruating woman can be ignored temporarily; repeat the urinalysis at mid-cycle.
  • Remember that there are other less common causes of spurious haematuria – sometimes the blood may be coming from the rectum or vagina. Assess each case carefully and be prepared to rethink if symptoms persist but urological investigations prove negative.
  • Some food pigments, beetroot and certain drugs (e.g. nitrofurantoin) can colour the urine red – confirm haematuria with urinalysis to save the patient unnecessary tests.

Red Flags

  • Painless frank haematuria is an ominous sign indicating possible malignancy.
  • Beware of recent onset of recurrent cystitis with haematuria in the elderly. The underlying cause may be a bladder tumour, especially if the haematuria (micro- or macroscopic) does not settle with treatment of the infection.
  • Renal tumours can sometimes present with renal colic, as blood clots in the ureters mimic the effects of stones. A useful clue is that the bleeding may precede the pain.
  • Haematuria requires emergency admission if there is significant blood loss or clot retention.
  • Remember the possibility of chronic ketamine abuse in young people.
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Website disclaimer

Pulse Reference is based on the best-selling book Symptom Sorter.

The experts behind Pulse Reference are Dr Keith Hopcroft who is the co-author of Symptom Sorter, a GP in Essex and Pulse’s editorial advisor and Dr Poppy Freeman, a GP in Camden and also a clinical advisor to Pulse.

This website is for clinical guidance only and cannot give definitive diagnostic information. Practitioners should work within the limits of their individual professional practice, seek guidance when necessary and refer appropriately.