Blood in your urine?

Author: Mr. Arjun Desai and Mr. Rajesh Nair

Date: May 2018

Blood in the urine (known as haematuria) is an important clinical sign that, whilst often painless, should not be ignored!


There are two types of haematuria:

1. Visible

Visible haematuria is blood mixed in the urine seen on urination. It may be bright or dark red or even a deeper brown colour. The blood may be associated with clots. It is important clinical sign that should never be ignored and must be investigated.

2. Non-visible

Non-visible haematuria occurs when microscopic amounts of blood are present in the urine. This is not seen with our eyes, but may be detected when a urine sample is provided to a health care practitioner. A urine dipstick test can be used in a health care setting to pick up this small amount, or it may be seen under the microscope when evaluating for infection.

Both are equally important to investigate in order to identify a cause. Kidney stones, urinary tract infections (UTIs), as well as blood from women’s menstrual cycles can be a potential cause of non-visible haematuria. However, the most important cause that healthcare professionals need to rule out is cancer within the urinary tract.

Causes of Haematuria:

1. Kidney Stones

Kidney stones can result in visible or non-visible haematuria. The stone can rub and irritate the lining of the kidney, ureter (tube draining urine out of the body) or bladder resulting in bleeding. For some patients, kidney stones may have no symptoms at all, particularly if they sit undisturbed in the kidney. Those who have symptoms, the most common is discomfort in the loin, for those patients passing kidney stones, this pain may be severe and travel down to the lower groin. Other presentations of kidney stones can include recurrent urinary tract infections.

2. Urinary Tract Infections and Kidney Infections

Urinary tract infections (more common in women) can result in visible and non-visible haematuria due to inflammation of the bladder lining. You may find yourself using the toilet more frequently and also notice pain or a burning sensation on passing urine. In some cases, lower abdominal discomfort and fevers and shakes may feature. Uncomplicated urinary tract infections are typically treated effectively with a short course of antibiotics and tend to resolve quickly. Complicated urinary tract infections (those with an underlying urological cause) may require longer courses of antibiotics and treatment of the underlying condition.

Kidney infections (known as pyelonephritis), results from inflammation in the kidneys due to the presence of bacteria, and can present with fevers and pain in the loin radiating down to the front of the abdomen. This is seen as more serious than a UTI and often results from a lower urinary tract infection of the bladder ascending towards the kidneys. Treatment may require a longer course of antibiotics and in some cases a short hospital stay to administer antibiotics through the vein.

If you have recurrent or frequent urinary tract infections, investigation with a specialist is recommended to exclude any underlying anatomical (problems with the anatomy of the urinary tract), or pathological (problems with disease of the urinary tract) causes.

3. Cancer

Haematuria may unfortunately also be an early red-flag for a more serious, underlying cancer of the urinary tract. If visible haematuria is present, chances that an underlying urinary tract cancer is present can be up to 20%, with non-visible haematuria, this is to less than 2%.

As haematuria is often the first symptom of an underlying cancer, the earlier they are identified, the earlier treatment strategies can be initiated.

Bladder Cancer

Bladder cancer affects around 10,000 people in the UK each year. Increasing age is one of the main risk factors for developing this cancer, and many of those diagnosed are found to be over the age of 60. There are a number of important preventable risk factors associated with bladder cancer. In particular, smoking, where bladder cancer is 2-6 times more likely to develop in a smoker than a non-smoker. Other risk factors include people who work in the petroleum based industry, work with chemical dyes or in some cases, there may be a genetic association.

When bladder cancer is identified, an important distinction must be made between those cancers which may prove to be a ‘nuisance’ rather than an imminent threat to life. This, is due to recurrent growths within the bladder which require monitoring and removal, versus those tumours which may potentially be a threat by limiting the length and quality of life.

Kidney Cancer

Kidney cancer affects around 12,000 people in the UK each year. Many people develop this cancer for no known reason, although increasing age, smoking, obesity and hypertension are known risk factors.

Most kidney cancers are small, not an imminent threat and are incidentally detected due to a scan being performed for another reason altogether. However, with larger kidney cancers, patients can have symptoms including blood in the urine, pain in the side or lower back, a swelling in the area over the kidney, and high temperatures and sweats. Many kidney cancers can be surgically removed, some by removal of the portion of the kidney affected by tumour (partial nephrectomy), sometimes through removal of the whole kidney (radical nephrectomy). In some circumstances, drug based therapy is required to control the kidney cancer spread.

The Referral and What to Expect?

It is clear that blood in the urine must be investigated. Any episode of painless haematuria should be referred to a urologist for further investigation, and if non-visible haematuria is detected on three separate occasions. Depending on what your general practitioner suspects is the cause for your haematuria you may either be given an appointment on an urgent or non-urgent basis at the local urological service.

Most well-functioning haematuria investigation services will try and complete investigations in one sitting. Often an appointment with a urologist will take place where a short medical history is obtained understanding the circumstances of blood in your urine and any contributing factors.

A series of investigations will be organised which include a urine dipstick test/analysis, a blood test, an ultrasound examination (an ultrasound scan is a procedure that uses high-frequency sound waves to create an image of part of the inside of the body) of the urinary tract for non-visible haematuria or referral for a CT-Scan (a computerised tomography (CT) scan uses X-rays and a computer to create detailed images of the inside of the body) for visible haematuria. Finally, in most circumstances, a telescopic examination of the bladder is performed under local anaesthetic called a flexible cystoscopy.

Flexible Cystoscopy

A flexible cystoscopy is a procedure used to view the inside of the bladder.

The flexible cystoscope used in this procedure is a pencil-thick fibre optic tube with a video camera and light at its tip. The scopes flexibility allows it to navigate and curl around the urinary system in order to allow the urologist to thoroughly and completely investigate the bladder. The procedure is performed under a local anaesthetic gel, and whilst you are awake for the procedure, rest assured, beyond some very mild discomfort the procedure itself should not be painful.

It is an important test to perform as the bladder needs to be visualised in particular to look for small cancers which may not be easily be detectable with the use of scans.


Blood in your urine may be bright pink, red or dark brown. It must be investigated, and whilst it usually is not caused by anything serious, it may be a sign of cancer. This is easier to treat if identified early. See your general practitioner or a specialist if you notice blood in your urine.

Article written by Mr. Arjun Desai - Final Year Medical Student, King’s College London. London, United Kingdom and Mr. Rajesh Nair - Consultant Urological Surgeon, Guy’s and St. Thomas’ NHS Foundation Trust, London, United Kingdom

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Next review: 24 May 2021