Introduction 

Finding blood in your urine can be very frightening and must be investigated by a doctor, but it's rarely a sign of anything life threatening.

If you notice bright red blood in your urine, or if your urine has turned reddish or brownish because it has red blood cells in it, see your GP.

Sometimes, urine may contain only a small amount of blood invisible to the naked eye and is only apparent in a laboratory when a urine test is carried out for something else. This will still need to be investigated by your doctor, as healthy urine should not contain any detectable amounts of blood.

The medical name for blood in the urine is haematuria. If the blood in the urine is obvious with the naked eye, it is called "macroscopic", or "visible haematuris". If the blood can only be detected with laboratory testing, it is called "microscopic", or "invisible".

The blood will have come from somewhere within the urinary tract – the kidneys, bladder or the tubes that urine passes through. It is often the result of a urinary tract infection (UTI) such as cystitis.

This page outlines the most common reasons for blood in the urine to give you an idea of what may be causing the problem. However, this guide should not be used to self-diagnose your condition, and it's important you see your GP for a proper diagnosis of the cause.

Is there definitely blood in the urine?

Before you read on, it is worth considering whether you have recently eaten beetroot, as this can colour the urine pink and cause unnecessary alarm. Also, some medicines, such as the antibiotic nitrofurantoin, can turn the urine brown or red.

Check that the blood is actually coming from your urine and not your vagina (if you're a woman) or back passage.

Common causes of blood in the urine

These include:

  • cystitis (a bladder infection), which typically causes a burning pain when you urinate.
  • kidney infection – you may also have a high temperature (38ºC or above) and pain in the side of your tummy
  • kidney stones, which may be painless but can sometimes block one of the tubes coming from your kidneys and cause severe tummy pain
  • inflammation of the urethra, the tube that carries urine out of the body – this is known as urethritis, and is often caused by the sexually transmitted infection chlamydia
  • an enlarged prostate gland – this is a common condition in older men and nothing to do with prostate cancer: an enlarged prostate gland will press on the bladder and cause problems such as difficulty urinating and a frequent need to urinate
  • prostate cancer – this is usually only seen in men aged over 50 and usually progresses very slowly: it can often be cured if caught and treated early
  • bladder cancer – again, this is usually only the cause in people aged over 50
  • kidney cancer – this usually affects adults aged over 50, is often detected on scans done for other conditions, and can be cured if caught early

You can read more about these conditions by clicking on the above links.

Do I need to see a specialist?

Your GP should refer you urgently to a specialist, usually a urologist, if any of the following apply:

  • you have visible blood in your urine and no pain, and tests show there is no infection
  • you are 40 or over and keep getting urinary tract infections and blood in your urine
  • you are 50 or over and a urine test picks up unexplained blood in your urine
  • you have a mass in your abdomen (a possible tumour) that was picked up during physical examination by your doctor or via a scan
  • invisible haematuria is picked up in a test, particularly if there is also protein found in the urine – this will be investigated by a nephrologist (kidney specialist) rather than a urologist.

Questions your doctor may ask you

  • When did you first notice blood in your urine?
  • Do you have any other symptoms, such as burning when you urinate or pain in your tummy?
  • Do you feel you have to urinate more frequently?
  • Have you had this before?
  • Does your urine smell odd?
  • Have you recently eaten beetroot?
  • Do you smoke? (smoking is the most common cause of bladder cancer)

Kidney problems

What can go wrong with your kidneys and why, including kidney disease, kidney stones and kidney cancer

Page last reviewed: 14/01/2013

Next review due: 14/01/2015