Blood in Urine (Haematuria)
Understand the possible causes of blood in the urine, when it may need urgent assessment, and the tests used to identify underlying conditions.
Even a single episode of unexplained blood in the urine should not be ignored. Assessment can help identify the cause and determine whether further tests are needed.
What Is Blood in Urine?
Blood in the urine is known medically as haematuria.
There are two main types:
- Visible haematuria (gross haematuria): the urine appears pink, red, brown or cola-coloured.
- Non-visible haematuria (microscopic haematuria): blood is detected only on a urine test or under a microscope.
The amount of blood seen does not always reflect the seriousness of the underlying cause. Even small amounts of blood that are only found on testing may require further evaluation.
When Should Blood in Urine Be Checked?
Any unexplained episode of visible blood in the urine should be assessed by a doctor.
Microscopic haematuria may also require further evaluation, particularly if it persists or occurs alongside other symptoms or risk factors.
Seek prompt medical attention if blood in the urine occurs with:
- Blood clots in the urine
- Difficulty passing urine or inability to urinate
- Fever or chills
- Severe pain in the side, back or lower abdomen
- Burning or pain when passing urine
- Unexplained weight loss
- Persistent urinary urgency or frequency
- Swelling of the legs or face
- Recurrent episodes of haematuria
What Causes Blood in Urine?
Blood in the urine can arise from anywhere within the urinary tract, including the kidneys, ureters, bladder, prostate and urethra.
Common Causes
Urinary Tract Infection (UTI)
Infections affecting the bladder, kidneys or urinary tract can irritate the lining of the urinary system and cause bleeding.
Symptoms may include:
- Burning or discomfort when passing urine
- Frequent urination
- Sudden urgency to urinate
- Cloudy or strong-smelling urine
- Lower abdominal discomfort
- Fever or flank pain in more severe infections
Kidney Stones or Ureteric Stones
Stones can scratch or irritate the urinary tract as they move, leading to visible or microscopic blood in the urine.
Symptoms often include:
- Sudden severe pain in the back, side or groin
- Nausea or vomiting
- Difficulty finding a comfortable position
- Urinary urgency or frequency
Enlarged Prostate (Benign Prostatic Hyperplasia)
An enlarged prostate can affect urine flow and occasionally cause bleeding.
Symptoms may include:
- Weak urine stream
- Difficulty starting urination
- Frequent urination, especially at night
- A feeling of incomplete bladder emptying
Vigorous Exercise
Intense physical activity, particularly endurance sports such as long-distance running, can occasionally cause temporary haematuria.
If blood in the urine persists beyond 48 to 72 hours after exercise, further assessment is recommended.
Medications
Some medications can increase the risk of bleeding or affect the urinary tract.
These include:
- Anticoagulants (blood thinners)
- Antiplatelet medications
- Certain chemotherapy drugs
Medication-related haematuria still requires evaluation, as blood thinners may reveal an underlying condition rather than being the sole cause.
Less Common but Important Causes
Kidney Disease
Conditions affecting the filtering units of the kidneys, such as glomerulonephritis, may cause blood and protein to leak into the urine.
Other signs may include:
- High blood pressure
- Swelling of the ankles, feet or face
- Foamy urine
- Reduced kidney function on blood tests
Trauma or Recent Procedures
Injury to the kidneys or urinary tract, or recent procedures such as catheter insertion, may result in temporary bleeding.
Urinary Tract Cancers
Blood in the urine can be an early symptom of cancers affecting the urinary tract, including:
- Bladder cancer
- Kidney cancer
- Ureteric cancer
- Urethral cancer
- Prostate cancer
Visible blood in the urine that occurs without pain is a recognised warning sign of bladder cancer, although many people with haematuria do not have cancer.
Does Blood in Urine Always Mean Cancer?
No. Most cases of haematuria are caused by non-cancerous conditions such as infections, kidney stones or prostate enlargement.
However, urinary tract cancers can sometimes cause blood in the urine without any other symptoms.
The likelihood of an underlying cancer is higher in people with certain risk factors, including:
- Age over 40 years
- Current or previous smoking
- Occupational exposure to industrial chemicals or dyes
- Previous pelvic radiotherapy
- Recurrent urinary tract infections
- A personal or family history of urinary tract cancers
- Long-term catheter use
Because it is not possible to determine the cause based on symptoms alone, unexplained haematuria should be investigated.
How Is Blood in Urine Investigated?
The tests recommended will depend on factors such as your age, symptoms, medical history and individual risk factors.
Medical History and Physical Examination
Your doctor may ask about:
- When the bleeding started
- Whether the urine is consistently discoloured or changes during urination
- The presence of pain or urinary symptoms
- Recent infections or exercise
- Previous kidney stones or urinary problems
- Smoking history
- Current medications
- Family history of kidney or bladder disease
A physical examination may include checking your abdomen, blood pressure and, when appropriate, a prostate examination.
Urine Tests
Urine tests help confirm the presence of blood and identify possible causes.
These may include:
- Urine dipstick testing
- Microscopic urine analysis
- Urine culture to check for infection
- Urine protein testing
- Urine cytology in selected cases
Blood Tests
Blood tests may assess:
- Kidney function
- Full blood count
- Signs of infection or inflammation
- Blood clotting function
- Prostate-specific antigen (PSA) levels when appropriate
Imaging Tests
Imaging studies help examine the kidneys and urinary tract for stones, tumours or structural abnormalities.
Depending on your symptoms and risk factors, this may include:
- Ultrasound of the kidneys and bladder
- CT scan or CT urogram
- MRI in selected situations
Flexible Cystoscopy
A flexible cystoscopy allows direct examination of the urethra and bladder using a thin camera passed through the urinary passage.
This procedure can help identify:
- Bladder tumours
- Bladder stones
- Areas of inflammation or bleeding
- Structural abnormalities
- Prostate enlargement affecting the bladder outlet
Flexible cystoscopy is commonly performed as an outpatient or day procedure using local anaesthetic gel.
How Is Blood in Urine Treated?
Treatment depends on the underlying cause identified during assessment.
Examples include:
- Antibiotics for urinary tract infections
- Medications or procedures for an enlarged prostate
- Treatment for kidney or ureteric stones
- Specialist management of kidney disease
- Procedures or therapies for urinary tract cancers
In some cases, no significant abnormality is found. Your doctor may recommend repeat urine testing or follow-up monitoring, depending on your individual circumstances.
Frequently Asked Questions
I saw blood in my urine once, but it disappeared. Do I still need to be checked?
Yes. Even a single episode of unexplained visible blood in the urine should be assessed, particularly in adults over 40 years of age or those with risk factors such as smoking.
Can dehydration cause blood in the urine?
Dehydration does not usually cause haematuria directly, but it may increase the risk of conditions such as kidney stones, which can lead to bleeding.
Is blood in the urine always painful?
No. Haematuria may occur with or without pain. Painless visible blood in the urine should always be evaluated.
Can foods or medications change the colour of urine?
Yes. Foods such as beetroot, blackberries and rhubarb, as well as certain medications, can cause red, pink or brown urine.
If you are unsure whether the colour change represents blood, seek medical advice.
What tests are usually needed?
Most people require urine testing and imaging of the urinary tract. Depending on your age, symptoms and risk factors, a cystoscopy may also be recommended.
Can blood thinners cause blood in the urine?
Blood-thinning medications can increase the likelihood of bleeding, but haematuria should not automatically be attributed to these medications without further assessment.
Can blood in urine come and go?
Yes. Some causes, including kidney stones, infections and bladder tumours, may cause intermittent bleeding. Even if the blood disappears, assessment is still recommended.
What colour can blood in urine be?
Urine may appear pink, red, brown or cola-coloured. Sometimes blood is only detected on urine testing and cannot be seen with the naked eye.
When Should I Arrange an Assessment?
Consider arranging a urological assessment if you:
- Notice visible blood in your urine
- Have persistent microscopic blood in the urine
- Experience recurrent urinary tract infections
- Have ongoing urinary symptoms such as urgency, frequency or difficulty passing urine
- Develop flank pain or recurrent kidney stones
- Have risk factors such as smoking or a family history of urinary tract cancers
Investigating haematuria helps identify the underlying cause and determine whether treatment or ongoing monitoring is needed.
Consultation with Dr Roger Anthony Idi can be arranged through Prince Court Medical Centre.