Blood in the urine — when is it serious?

Medical author: Jakub Gondek, MD, urologist — subject to approval before publication · Editorial preparation: Wyspa Medycyny Przyjaznej Editorial Team · Medical review: Jakub Gondek, MD — to be confirmed before publication · Creation date: 10 July 2026 · Review date: to be completed after approval · Updated: 10 July 2026

This article is educational and does not replace a urology consultation or urgent medical care. Visible blood in the urine, blood clots, urinary retention, fever, chills, severe flank pain, marked weakness, fainting, pregnancy, having only one kidney, or haematuria in a person taking anticoagulants require urgent contact with a doctor.

Key information at a glance

• Blood in the urine always requires investigation — even if it occurred only once, the amount was small or there was no pain.
• Visible haematuria means that the urine appears pink, red, brown, tea-coloured or contains blood clots.
• Microscopic haematuria means that red blood cells are found in a urine test even though the patient cannot see blood with the naked eye.
• Haematuria may be caused by infection, stones, prostatitis, benign prostate enlargement, trauma, intense exercise, a urological procedure, kidney disease or a urinary tract tumour.
• Painless visible haematuria is particularly important diagnostically — the absence of pain should not be reassuring.
• Blood in the urine accompanied by fever, chills and flank pain may suggest a kidney infection or infection with obstructed urine flow and requires urgent assessment.
• Blood in the urine with severe flank pain may occur with a ureteral stone, but flank pain does not always mean a stone.
• Anticoagulants may worsen bleeding, but they should not be stopped without medical advice. Haematuria in a patient taking such medicines still requires investigation.
• A normal ultrasound does not always complete the evaluation of haematuria. Depending on the situation, cystoscopy, CT, urinalysis, urine culture or nephrology consultation may be required.
• The most important question is not “is this definitely something serious?”, but “where is the blood coming from and are we missing a serious cause?”.

Learn more about the specialist

Jakub Gondek, MD, is a urologist at Wyspa Medycyny Przyjaznej in Gdańsk. He diagnoses and treats diseases of the urinary and reproductive systems, including urinary problems, symptoms of prostate disease, suspected urinary tract infections, pain in the urinary tract area and abnormal urine test results.

Meet Jakub Gondek, MD

Does this topic make sense for SEO, AI and Google Search?

Yes. Patients very often search for answers to questions such as: “what does blood in urine mean”, “blood in urine without pain”, “is haematuria cancer”, “blood in urine and burning”, “blood in urine and flank pain”, “haematuria in men”, “microscopic haematuria”, “bladder cancer symptoms”, “stones and blood in urine” and “when to see a urologist for blood in urine”. This is a high-intent medical topic that requires calm but unequivocal language.

For haematuria, E-E-A-T is particularly important: a named medical author, an update date, sources, warning symptoms, oncological caution and an explanation that haematuria may have benign causes but should not automatically be attributed to infection, stones or anticoagulants.

What is haematuria?

Haematuria means the presence of blood or red blood cells in the urine. It may be visible to the naked eye or detected only in a laboratory test. Visible haematuria may make the urine pink, red, brown, dark or tea-coloured. Blood clots may also occur.

Microscopic haematuria means that the patient does not see any change in urine colour, but urinalysis shows red blood cells. This result also requires interpretation, particularly if it recurs or is accompanied by protein in the urine, high blood pressure, impaired kidney function or risk factors for urological disease.

It is worth remembering that not every red discolouration of urine is blood. Beetroot, some food colourings, dehydration, medicines and supplements may change the colour of urine. However, if the urine appears red, pink or brown, or the patient is unsure whether it is blood, a urine test should be performed and the result discussed with a doctor.

Blood in the urine — common causes

Haematuria may originate from the kidneys, ureters, bladder, prostate or urethra. The cause may be benign, but it can also be serious, so it is not advisable to guess based on urine colour alone.

This table is not intended for self-diagnosis. It shows that the same symptom — blood in the urine — may have very different causes and requires appropriate testing.

Visible blood in the urine — why should you not wait?

Visible blood in the urine is not a symptom that should be watched for months. Even if it occurred only once, stopped on its own and caused no pain, it should be investigated. This is particularly important in people over 45, smokers, people with recurrent haematuria, blood clots, bladder symptoms or risk factors for cancer.

Patients often delay because they attribute the symptom to beetroot, infection, exercise, a stone or anticoagulants. Some of these explanations may indeed be correct, but they should not be accepted without verification. Haematuria is too important to diagnose merely by looking at the colour.

The safest approach is to perform urinalysis and consult a doctor, particularly if the episode recurs, the urine contains clots or other symptoms appear.

Painless haematuria — can it be serious?

Yes. The absence of pain does not mean that the symptom is harmless. Painless visible haematuria is one of the symptoms that particularly requires urological investigation because it may occur with diseases of the bladder, kidneys and upper urinary tract.

An infection usually causes additional symptoms such as burning, frequent urination, urgency or lower-abdominal pain. Stones often cause flank pain. If haematuria occurs without pain, burning or an obvious cause, the fact that “nothing hurts” should not be reassuring.

Depending on age, symptoms and risk factors, the doctor may consider urinalysis, urine culture, ultrasound, CT of the urinary tract or cystoscopy.

Blood in the urine and burning — an infection or something more?

Blood in the urine accompanied by burning, frequent urination, urgency and lower-abdominal pain often suggests a urinary tract infection. Urinalysis is the basic test, and urine culture may be needed in selected cases. In men, urinary tract infections more often require a more detailed assessment than in young healthy women because they may be associated with the prostate, residual urine, stones or another urological cause.

If haematuria occurs during an infection, it is important that it resolves after treatment. Haematuria that persists after successful treatment of a UTI requires further diagnostics. Repeatedly treating an assumed “infection” without confirmation is not appropriate when blood in the urine recurs or the results are unclear.

Blood in the urine and flank pain — when should stones be suspected?

Blood in the urine accompanied by severe flank or lower-back pain radiating to the groin, testicle, labia or lower abdomen may suggest a ureteral stone. Nausea, vomiting, restlessness and waves of worsening pain are also common.

Not every flank pain is caused by a stone, and not every stone can safely be managed at home. Urgent assessment is particularly important when flank pain is accompanied by fever, chills, vomiting, urinary retention, a solitary kidney, pregnancy or deterioration in general health. Infection with obstructed urine flow may be dangerous.

To diagnose stones, the doctor may order urinalysis, blood tests, urinary tract ultrasound or CT if the picture is unclear or the stone must be assessed precisely.

Blood in the urine in a man — is it the prostate?

In men, haematuria may be related to the prostate, but this should not be assumed automatically. Prostatitis, benign prostate enlargement, infection, urinary retention or a prostate procedure may cause blood in the urine. However, the bladder, kidneys and ureters must also be considered.

If haematuria occurs together with a weak urinary stream, difficulty starting urination, frequent night-time urination or a feeling of incomplete bladder emptying, the urologist may assess the prostate, residual urine, urinalysis, PSA and ultrasound. This does not mean that the prostate is the only possible cause.

Particular caution is required with painless visible haematuria in men over 45, smokers and people with recurrent symptoms.

Blood in the urine and anticoagulants

Patients taking anticoagulant or antiplatelet medicines may be more prone to bleeding. However, this does not mean that haematuria can automatically be attributed to the medicines. They may reveal bleeding from an existing cause, such as a bladder tumour, stone, inflammation or another urinary tract condition.

Anticoagulants should not be stopped without medical advice because this may increase the risk of thrombosis, stroke or other complications. The patient should contact a doctor who will assess the urgency, severity of bleeding, indication for the medicine and need for further diagnostics.

Haematuria with blood clots, urinary retention, weakness, low blood pressure, fainting or major blood loss requires urgent medical help.

Microscopic haematuria — is it also important?

Yes. Microscopic haematuria, meaning red blood cells detected in urinalysis, requires interpretation. Sometimes it is temporary and related to infection, exercise, menstruation, trauma or sample contamination. In other cases, it persists and requires further investigation.

It matters whether the result recurs and whether it is accompanied by proteinuria, casts, high blood pressure, swelling, deterioration in creatinine, infection symptoms, flank pain or risk factors for urological disease. Some patients require urological assessment and others also need nephrology assessment.

A single urine dipstick should not be relied upon without confirmation. Full urinalysis with sediment examination provides more information and helps distinguish haematuria from other abnormalities.

When does blood in the urine require urgent help?

Some situations require prompt medical assessment rather than waiting for a routine appointment. Urgent help is needed in the case of:

• visible blood in the urine with blood clots,
• inability to urinate or increasing urgency without passing urine,
• fever, chills, marked weakness or suspected infection,
• severe flank or lower-back pain,
• nausea and vomiting preventing drinking or taking medicines,
• fainting, dizziness, pallor or signs of major blood loss,
• pregnancy,
• a solitary kidney, transplanted kidney or known kidney disease,
• haematuria in a person taking anticoagulants, especially if heavy,
• haematuria after trauma to the abdomen, back or pelvis,
• haematuria in a child, older person or immunocompromised patient.

In such situations, urgent medical care, an emergency department or hospital admission unit may be appropriate, particularly if the patient’s condition is worsening.

When should you see a urologist?

A urologist should be consulted after every episode of visible blood in the urine, particularly when it recurs, occurs without pain, includes clots or the patient has risk factors for bladder or kidney disease.

A urology consultation is particularly recommended when:

• blood was visible to the naked eye,
• haematuria occurred without pain or infection symptoms,
• haematuria recurs,
• urinalysis repeatedly shows red blood cells,
• the patient is over 45,
• the patient currently smokes or previously smoked,
• there is flank pain, suspected stones or kidney obstruction,
• there are bladder symptoms: frequency, urgency, burning, pain or difficulty urinating,
• haematuria persists after treatment of an infection,
• there is unintended weight loss, weakness, anaemia or deterioration in kidney results.

How is blood in the urine investigated?

The diagnostic approach depends on whether haematuria was visible or microscopic, whether pain, fever, infection, stones, kidney disease or bladder symptoms are present, and on the patient’s age and risk factors. No single test answers every question in every situation.

The doctor may consider:

• urinalysis with sediment examination — confirms red blood cells and may show white blood cells, protein, nitrites, casts or crystals,
• urine culture — when infection is suspected, especially with fever, recurrence or unusual symptoms,
• blood tests — complete blood count, creatinine, eGFR, CRP or other parameters depending on the situation,
• urinary tract ultrasound — assessment of the kidneys, bladder, residual urine, obstruction, tumours, stones and prostate,
• CT or CT urography — when the kidneys, ureters or the cause of haematuria need to be assessed more precisely,
• cystoscopy — examination of the inside of the bladder and urethra, particularly important in visible haematuria or suspected bladder disease,
• urine cytology — in selected situations when specific urothelial conditions are suspected,
• nephrology consultation — when the result suggests kidney disease, such as proteinuria, casts, impaired kidney function or high blood pressure.

Good haematuria diagnostics aims to determine whether the blood comes from the lower urinary tract, upper urinary tract, prostate, kidney filtration structures or a temporary factor that has already resolved.

Ultrasound, CT or cystoscopy — which test is needed?

Urinary tract ultrasound is often one of the first imaging tests because it can assess the kidneys, bladder, residual urine, obstruction, larger tumours, some stones and the prostate. However, it does not always show every cause of haematuria. Small bladder lesions, some ureteral lesions or small stones may require other tests.

CT, particularly CT urography, may be needed when the doctor wants a more detailed view of the kidneys, ureters and upper urinary tract. Cystoscopy allows the bladder to be viewed from the inside and is very important in the evaluation of visible haematuria, particularly when bladder disease must be excluded.

Patients often ask: “is ultrasound enough?”. The answer depends on age, symptoms, urine results, risk factors and whether the haematuria was visible. For some patients, ultrasound is only the beginning of the diagnostic process.

Can blood in the urine mean cancer?

It can, but it does not necessarily. This distinction is very important. Haematuria has many causes, and infection or stones are common. At the same time, visible blood in the urine, particularly without pain, is one of the symptoms that requires exclusion of urinary tract cancers, including bladder, kidney and upper urinary tract cancer.

Risk increases with age, smoking, occupational exposure to certain chemicals, previous urological disease, pelvic radiotherapy, chronic inflammation and recurrent haematuria.

The urologist’s role is not to frighten the patient with cancer, but to responsibly exclude serious causes. It is better to complete diagnostics and receive a reassuring answer than to spend months assuming the symptom is “probably an infection”.

Blood in the urine after exercise, cycling or training

In some people, haematuria may occur temporarily after very intense exercise, long-distance running, cycling, trauma or heavy physical strain. It should resolve after rest and hydration, but should not recur without explanation.

If the blood is visible, appears repeatedly, is accompanied by pain, clots, burning or fever, or does not resolve, it should not be attributed only to training. Physically active people may also develop stones, infections, kidney disease and bladder disease.

What should you not do when there is blood in the urine?

With haematuria, it is important to avoid actions that may delay diagnosis or worsen the situation. You should not:

• automatically assume it is an infection or a stone,
• take antibiotics without urinalysis and a doctor’s decision,
• stop anticoagulants without medical advice,
• ignore haematuria because it is painless,
• assume that a single episode is insignificant,
• rely only on urine colour without urinalysis,
• wait for weeks when there are clots, fever, flank pain or urinary retention,
• treat a normal ultrasound as definitive exclusion of every cause when the symptom was alarming,
• delay consultation because of embarrassment or fear of cystoscopy.

Blood in the urine does not immediately mean the worst-case scenario. It does mean that the cause must be found.

Common myths about blood in the urine

• “It happened only once, so there is no problem.” False. Even a single episode of visible haematuria should be investigated.
• “If it does not hurt, it is not dangerous.” False. Painless haematuria may be an important warning symptom.
• “It is probably cystitis.” It may be, but infection should be confirmed and haematuria should resolve after treatment.
• “It is caused by anticoagulants, so no tests are needed.” False. These medicines may increase bleeding but do not exclude bladder, kidney or prostate disease.
• “The ultrasound was normal, so nothing is wrong.” Not always. Cystoscopy, CT or further diagnostics may still be needed.
• “Blood in the urine always means cancer.” False. There are many possible causes, but cancer must be responsibly excluded when indicated.
• “Microscopic haematuria is unimportant.” False. If it recurs or is accompanied by other abnormalities, it requires interpretation.
• “Young age excludes a serious cause.” False. Cancer risk increases with age, but younger patients with haematuria also require assessment.

Have you noticed blood in your urine?

Do not wait for the problem to “explain itself”. A urologist can assess whether the cause is an infection, stones, the prostate, kidney disease, bladder disease or another problem requiring diagnostics.

Haematuria diagnostics at Wyspa Medycyny Przyjaznej in Gdańsk

At Wyspa Medycyny Przyjaznej, patients with blood in the urine, an abnormal urinalysis result, flank pain, suspected stones, urinary infection symptoms, urinary difficulties or prostate symptoms may begin diagnostics with a urology consultation.

Jakub Gondek, MD, can assess symptoms, medical history, urine results and previous imaging, and decide whether urinalysis, urine culture, blood tests, urinary tract ultrasound, prostate assessment, residual urine measurement, referral for CT, cystoscopy or further specialist diagnostics are needed.

The aim of the consultation is not to cause anxiety, but to safely identify the source of haematuria. In many cases the cause is treatable, but visible blood in the urine requires a responsible approach.

Learn more about Jakub Gondek, MD Urological ultrasound Urology

What should you ask the urologist about blood in the urine?

• Was my haematuria visible or microscopic?
• Does the urine test confirm red blood cells?
• Are there signs of infection and do I need a urine culture?
• Do I need creatinine, eGFR, a complete blood count or CRP?
• Could the symptoms indicate stones?
• Should I have urinary tract ultrasound?
• Is cystoscopy needed in my situation?
• Do I need CT or CT urography?
• Could my anticoagulants affect the bleeding, and who should assess them?
• Could the result suggest kidney disease and a need for nephrology consultation?
• Which symptoms require urgent help?
• When should I return for follow-up?

FAQ — blood in the urine and haematuria

Does blood in the urine always mean something serious?

Not always. The cause may be an infection, stones, exercise, prostatitis or another treatable problem. However, blood in the urine always requires explanation because it may also be a sign of a more serious disease.

Is painless blood in the urine dangerous?

It may be an important warning symptom. The absence of pain does not exclude disease of the bladder, kidneys or upper urinary tract. Painless visible haematuria requires urological consultation.

Does blood in the urine mean cancer?

It does not necessarily mean cancer, but bladder, kidney and upper urinary tract cancers are among the causes that must be excluded, particularly with painless, visible or recurrent haematuria.

Can blood in the urine be caused by infection?

Yes. A urinary tract infection may cause haematuria, usually with burning, frequency, urgency or pain. The haematuria should resolve after successful treatment. If it persists, further diagnostics are needed.

Do blood in the urine and flank pain mean a stone?

They may suggest a ureteral stone, especially when the pain is severe and radiates to the groin. Other conditions may cause similar symptoms, so diagnostics are needed, particularly with fever, vomiting or severe pain.

Do anticoagulants explain blood in the urine?

They may worsen bleeding but do not exclude another cause. Haematuria in a person taking anticoagulants still requires assessment. The medicines should not be stopped without medical advice.

Is microscopic haematuria important?

Yes, especially if it recurs or is accompanied by proteinuria, casts, high blood pressure, impaired kidney function, pain, infection or urological risk factors.

Which tests are performed for blood in the urine?

The scope depends on the situation. Tests may include urinalysis, urine culture, complete blood count, creatinine/eGFR, urinary tract ultrasound, CT, cystoscopy, urine cytology or nephrology consultation.

When does blood in the urine require urgent help?

Urgent help is required for haematuria with blood clots, urinary retention, fever, chills, severe flank pain, vomiting, fainting, marked weakness, after trauma, during pregnancy, with a solitary kidney or known kidney disease.

Does a normal ultrasound exclude the cause of haematuria?

Not always. Ultrasound is very useful but does not detect every cause of haematuria. Depending on symptoms and risk, cystoscopy, CT or further tests may be needed.

Who assesses blood in the urine at WMP?

At Wyspa Medycyny Przyjaznej, urology consultations are provided, among others, by Jakub Gondek, MD, who diagnoses urinary and reproductive system diseases, urinary problems, suspected infection, stones and abnormal urine test results.

Sources for medical and editorial verification

• Wyspa Medycyny Przyjaznej, Jakub Gondek, MD: https://www.wyspamedycynyprzyjaznej.pl/pl/jakub-gondek
• Wyspa Medycyny Przyjaznej, urology consultation: https://www.wyspamedycynyprzyjaznej.pl/pl/konsultacja-urologiczna
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• Wyspa Medycyny Przyjaznej, urinary tract infections: https://www.wyspamedycynyprzyjaznej.pl/pl/zakazenia-ukladu-moczowego-blog
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