Blood in Urine (Hematuria)

Seeing blood in your urine can understandably be alarming. Sometimes it is caused by a relatively straightforward condition such as a urinary tract infection or kidney stone. In other cases, it can be a sign of a sinister condition that needs further investigation.

What Is Haematuria?

Haematuria means blood is present in the urine. It can be classified into two broad types:

• Visible haematuria – the urine appears pink, red, brown or tea-coloured because blood can be seen with the naked eye
• Non-visible haematuria (microscopic haematuria) – blood cannot be seen, but red blood cells are detected through urine testing

Microscopic haematuria should not automatically be dismissed simply because the urine looks normal. When confirmed on microscopic urine testing, its significance depends on factors such as the amount and persistence of blood, age, smoking history and other clinical risk factors.

Is Blood in Urine Always a Sign of Cancer?

Most cases of haematuria are not caused by cancer. Urinary tract infections, kidney or urinary stones, prostate conditions, kidney disease and certain medications can also cause blood to appear in the urine.

However, haematuria can sometimes be an early sign of cancer affecting the bladder, kidneys or other parts of the urinary tract. Some urinary tract cancers can cause painless visible haematuria without other obvious symptoms.

Further assessment is especially important when:

• The cause is unclear and there is no obvious infection, stone or other explanation 
• Blood is visible in the urine 
• Haematuria keeps returning after apparently resolving 
• You have risk factors for urinary tract or kidney cancer 

Being referred for investigation does not mean that you have cancer. The purpose is to determine the cause and identify any condition that may require treatment.

What Causes Blood in Urine?

The urinary system extends from the kidneys to the bladder and urethra, so bleeding can occur at different points along this pathway.

It may include:

• Urinary infections – urinary tract infections (UTIs) can inflame the urinary tract and cause blood in the urine, often alongside burning, urgency or increased frequency
• Kidney and urinary stones – kidney or ureteric stones can irritate the urinary tract as they move, causing bleeding and sometimes severe flank, abdominal or groin pain
• Prostate conditions – an enlarged prostate, inflammation or other prostate conditions can cause haematuria, sometimes alongside a weak stream, hesitancy or incomplete bladder emptying
• Kidney conditions – certain kidney diseases can cause blood to leak into the urine and may require both urological and kidney-related assessment
• Medications and bleeding disorders – blood-thinning medications and certain bleeding disorders can make urinary bleeding more likely or noticeable, although haematuria should not automatically be attributed to medication
• Urinary tract injury – trauma to the kidneys, bladder or urinary tract can cause haematuria and may require urgent assessment when the injury is significant
• Urinary tract cancers – cancers affecting the bladder, kidneys or upper urinary tract can cause haematuria, particularly when the bleeding is unexplained

What Symptoms May Occur Alongside Haematuria?

The condition itself is a finding rather than a disease, so the symptoms can vary depending on its underlying cause.

As such, possible symptoms include:

• Pink, red or brown urine – visible blood may change the colour of the urine
• Blood clots in the urine – larger amounts of bleeding can sometimes produce clots, which may occasionally interfere with urine flow
• Burning or pain when urinating – this may occur when infection or inflammation is responsible
• Frequent or urgent urination – increased urinary frequency or urgency can accompany infection or other bladder conditions
• Lower abdominal discomfort – bladder inflammation and other urinary conditions may cause discomfort in the lower abdomen
• Flank or back pain – pain in the side or back may occur with kidney stones or certain kidney conditions

Who Is at Higher Risk of Haematuria From a Serious Underlying Condition?

Not everyone with haematuria has the same likelihood of an underlying serious condition. Our urologist may consider factors such as:

• Increasing age – the risk of urinary tract conditions, including bladder and other urological cancers, generally increases with age as cumulative cellular damage and long-term exposure to risk factors can contribute to abnormal cell changes
• Family or genetic history – certain inherited genetic conditions can increase susceptibility to kidney or urinary tract cancers, while a family history may indicate an underlying hereditary tendency
• Previous urological conditions – a history of recurrent urinary infections, urinary stones or other urinary tract conditions may be relevant when determining the likely cause of haematuria and which investigations are appropriate
• Previous cancer treatment – previous radiotherapy and some chemotherapy medicines, particularly cyclophosphamide, can cause long-term irritation or damage to the bladder lining and increase the risk of urothelial cancer
• Occupational exposures – long-term exposure to certain industrial chemicals, including aromatic amines, can expose the urinary tract to carcinogenic substances associated with urothelial cancer
• Smoking history – chemicals from tobacco smoke enter the bloodstream, are filtered by the kidneys and become concentrated in urine, where they can come into contact with the bladder lining and increase the risk of urothelial cancer

When Does Blood in Urine Require Urgent Medical Attention?

While haematuria is not always an emergency, certain symptoms should not be ignored. Seek prompt medical attention if you experience:

• Heavy or persistent bleeding – particularly when the urine remains visibly red or the amount of blood appears to be increasing 
• Blood clots in the urine – larger clots can occasionally obstruct the flow of urine 
• Difficulty or inability to pass urine – this can occur when clots block the urinary outlet and may require urgent treatment 
• Blood in the urine after significant injury – haematuria following trauma to the abdomen, back or pelvis should be assessed promptly
• Severe flank, abdominal or back pain – particularly when accompanied by blood in the urine, as this may occur with urinary stones or other acute urinary conditions 
• Fever, chills or feeling significantly unwell – especially when accompanied by urinary symptoms, as this may indicate a more significant infection 
• Dizziness, weakness or fainting – particularly if there has been substantial or ongoing bleeding

How Is Blood in Urine Diagnosed in Singapore?

The first step is to determine whether blood is genuinely present and then identify where it may be coming from.

This involves:

• Medical review – our urologist will ask about when the bleeding started, whether it is visible, whether it has happened before and whether you have symptoms such as pain, burning, urinary frequency or difficulty passing urine. Your medical history, medications, smoking history, previous urinary conditions and other risk factors will also help determine the appropriate investigations.
• Urine testing – a urine dipstick may detect blood, but microscopic examination can help confirm whether red blood cells are actually present. Urine culture may also be performed when infection is suspected. 
• Blood tests – blood tests may assess kidney function, blood counts or other findings relevant to the suspected cause.
• Imaging – depending on the clinical situation, imaging may include ultrasound, computed tomography (CT) urography or other urinary tract imaging. The choice depends on the suspected cause and the individual's risk profile.
• Cystoscopy – the procedure involves passing a small camera through the urethra to examine the inside of the bladder directly.

What Happens If Blood Is Found in My Urine?

The next step is to determine where the bleeding may be coming from and whether further investigation is required. The extent of testing depends on factors such as whether the blood is visible or microscopic, your age, symptoms, smoking history and other clinical risk factors.

Not every patient requires exactly the same investigations. Some may need repeat urine testing or treatment for an obvious infection, while others may require urinary tract imaging and cystoscopy.

How Is Haematuria Treated in Singapore?

There is no single treatment for haematuria because it is a symptom or clinical finding rather than a disease.

The treatment may involve:

• Urinary infection – antibiotics may be prescribed when a bacterial infection is diagnosed and treatment is clinically appropriate
• Stone treatment – kidney or urinary stones may require observation, medication or a procedure depending on their size, location and symptoms
• Prostate treatment – if an enlarged or inflamed prostate is responsible, treatment can be directed at the underlying prostate condition
• Treatment of kidney disease – where the source is a kidney condition, assessment by the appropriate specialist may be required
• Treatment of urinary tract abnormalities – structural problems, strictures or other abnormalities may require targeted treatment
• Cancer treatment – if haematuria is caused by a urinary tract cancer, treatment depends on the type and stage of the cancer

When Should I See a Urologist for Blood in the Urine?

Blood in the urine can result from conditions ranging from urinary infections and stones to problems affecting the kidneys, bladder or prostate. Because the cause cannot always be determined from symptoms alone, unexplained or recurrent haematuria may require further assessment.

Dr Joe Lee is a Senior Consultant Urologist who assesses conditions affecting the kidneys, urinary tract, bladder and prostate. Depending on your symptoms and risk factors, assessment may involve urine testing, imaging or cystoscopy where appropriate.

If you have noticed blood in your urine, particularly if it is visible, recurrent or unexplained, book an appointment with Dr Joe Lee to determine the possible cause and whether further investigation is required.