Small blood clots in urine usually mean that enough bleeding has occurred somewhere in the urinary tract for the blood to coagulate before leaving the body. Possible causes include urinary tract infections, kidney or bladder stones, an enlarged prostate, urinary procedures or trauma, bleeding disorders, certain medications, and cancers of the bladder or kidney. Visible urinary clots are a form of gross hematuria and should be medically evaluated, even when they are painless. (niddk.nih.gov)

What Does It Mean When You Pass Blood Clots in Urine?

Passing a blood clot in urine usually means that bleeding has occurred somewhere inside the urinary tract and some of that blood has clotted before being passed.

The urinary tract includes the:

• Kidneys

• Ureters

• Bladder

• Urethra

• Prostate in men

Blood may enter the urine from any of these structures.

A urinary blood clot is not the same as a deep vein thrombosis, pulmonary embolism, or another blood clot forming inside a vein or artery. In this situation, the clot generally forms because blood has entered the urinary system and coagulated there.

Visible blood in urine is known as gross hematuria. NIDDK notes that gross hematuria may make urine pink, red, or brown, and that blood clots can sometimes cause pain or obstruct urine flow. (niddk.nih.gov)

Because there are many possible causes, the size of a clot alone cannot tell you why the bleeding happened.

Are Blood Clots in Urine the Same as Hematuria?

Not exactly. Hematuria means blood in the urine, while a blood clot is coagulated blood that may form when there is enough visible bleeding.

There are two main types of hematuria:

Gross Hematuria

Gross hematuria is visible blood in the urine. The urine may look:

• Pink

• Bright red

• Dark red

• Brown or cola-colored

Visible clots can occur with gross hematuria.

Microscopic Hematuria

Microscopic hematuria means red blood cells are present in the urine but cannot be seen with the naked eye.

It is usually discovered through:

• Urinalysis

• Urine microscopy

Microscopic hematuria does not produce a visible urinary blood clot.

This distinction is important because a person searching for small or stringy blood clots in urine is dealing with visible urinary bleeding, not an incidental microscopic finding. (niddk.nih.gov)

What Do Blood Clots in Urine Look Like?

Urinary blood clots can vary considerably in appearance.

They may look like:

• Small dark-red clumps

• Jelly-like pieces

• Thin red strings

• Thread-like material

• Soft irregular fragments

• Larger dark clots mixed with red urine

The urine itself may also be pink, red, or brown.

It is important to distinguish urine discoloration from an actual clot. Red urine does not automatically mean there is blood. Certain foods, medications, hemoglobin, and muscle pigments can also change urine color. Merck Manual notes that beets, medications such as phenazopyridine, and several other substances can produce red or brown urine without true hematuria. (merckmanuals.com)

An actual jelly-like or stringy piece passed with urine is different from simple color change and should be evaluated.

Can Stringy or Worm-Like Material in Urine Be a Blood Clot?

Yes. A urinary blood clot can sometimes look stringy, thread-like, or even worm-like.

The shape of the urinary tract can mold soft clotted blood into elongated forms as it passes.

A published case report has documented a worm-like urinary blood clot, illustrating how coagulated blood can occasionally mimic a parasite or other foreign material. (pmc.ncbi.nlm.nih.gov)

However, appearance alone cannot confirm that a string-like object is blood.

If possible, tell the clinician:

• What color it was

• Approximately how large it was

• Whether it was stringy, jelly-like, or solid

• Whether the urine itself was red

• Whether it happened once or repeatedly

Mayo Clinic notes that clinicians evaluating hematuria may ask about the size and shape of blood clots as part of the history. (mayoclinic.org)

Where Do Blood Clots in Urine Come From?

Blood can enter the urine from virtually anywhere along the urinary tract.

Possible bleeding sites include:

Kidney → ureter → bladder → prostate → urethra

The fact that a visible clot has formed can provide some clinical context.

Merck Manual notes that urinary clots strongly suggest nonglomerular bleeding, meaning the bleeding is generally not coming from the microscopic kidney-filtering structures that cause many glomerular kidney diseases. (merckmanuals.com)

That does not allow someone to diagnose the exact bleeding site based on a clot.

Instead, it tells clinicians that a urologic source may need particular attention.

What Causes Small Blood Clots in Urine?

There are many possible causes. Some are common and treatable, while others require more urgent evaluation.

Urinary Tract Infection

A urinary tract infection can cause visible blood in urine and, when bleeding is sufficient, may occasionally be associated with small clots.

UTIs inflame the lining of the urinary tract, particularly the bladder.

Common symptoms include:

• Burning while urinating

• Frequent urination

• Strong urgency

• Lower abdominal or pelvic discomfort

• Cloudy urine

• Strong-smelling urine

• Visible blood

NIDDK includes infections and inflammation involving the bladder, urethra, kidney, or prostate among recognized causes of hematuria. (niddk.nih.gov)

If blood occurs with fever, chills, flank pain, vomiting, or significant illness, the infection may involve the kidneys and requires prompt medical assessment.

Kidney or Bladder Stones

Kidney and bladder stones can cause bleeding by irritating or injuring the lining of the urinary tract.

Stone-related bleeding often occurs with pain, although this is not universal.

Symptoms may include:

• Severe pain in the side or back

• Pain moving toward the groin

• Waves of intense pain

• Nausea

• Vomiting

• Urinary urgency

• Visible blood

NIDDK lists urinary stones among the common structural causes of hematuria. (niddk.nih.gov)

A stone can sometimes produce substantial enough bleeding for small clots to appear.

Enlarged Prostate or Prostate Bleeding

In men, especially older adults, an enlarged prostate may contribute to urinary bleeding.

Benign prostatic hyperplasia, or BPH, becomes increasingly common with age and can affect urine flow.

Associated symptoms may include:

• Weak urine stream

• Difficulty starting urination

• Dribbling

• Frequent urination

• Waking at night to urinate

• Feeling that the bladder has not emptied completely

BPH is one of the recognized causes of hematuria in older men. (niddk.nih.gov)

Visible blood in an older adult should still be evaluated rather than automatically attributed to an enlarged prostate.

Bladder or Kidney Cancer

Bladder and kidney cancers can cause visible blood in urine, and the bleeding may sometimes occur without pain.

This does not mean that blood clots in urine automatically indicate cancer.

Infections, stones, prostate conditions, and other benign causes are also common.

However, painless visible hematuria is an important reason clinicians investigate the urinary tract, especially in older adults or people with risk factors such as tobacco exposure.

MD Anderson identifies cancers of the bladder, kidney, and prostate among potential causes of hematuria. (mdanderson.org)

Visible clots should therefore be assessed rather than ignored simply because there is no pain.

Trauma or a Recent Urinary Procedure

Bleeding can occur after:

• Urinary catheter placement

• Cystoscopy

• Prostate biopsy

• Urinary surgery

• Significant pelvic or abdominal trauma

• Injury to the urinary tract

The amount and expected duration of bleeding depend on the procedure or injury.

If bleeding becomes heavier, clots become larger or more frequent, or urination becomes difficult, contact the treating clinician promptly.

Hemorrhagic Cystitis

Hemorrhagic cystitis means significant inflammation and bleeding from the bladder lining.

It can occur for several reasons, including certain infections, cancer treatments, radiation exposure, or medications.

Bleeding may range from mild visible hematuria to heavy bleeding with clots.

Severe cases can cause clot retention and require urgent urologic management.

Bleeding Disorders

Conditions that impair normal clotting can increase the chance of visible urinary bleeding.

Possible examples include:

• Hemophilia

• Platelet disorders

• Certain liver-related coagulation problems

• Other inherited or acquired bleeding disorders

When urinary blood occurs together with easy bruising, nosebleeds, gum bleeding, or bleeding elsewhere in the body, clinicians may consider a broader bleeding evaluation.

Can Blood Thinners Cause Blood Clots in Urine?

Blood-thinning medications can make urinary bleeding more noticeable, but visible blood should not simply be assumed to be caused by the medication.

Relevant medications may include:

• Warfarin

• Apixaban

• Rivaroxaban

• Dabigatran

• Aspirin

• Clopidogrel

Importantly:

Do not stop an anticoagulant or antiplatelet medication on your own because you notice blood in your urine.

Merck Manual emphasizes that anticoagulant use does not eliminate the need to investigate other potential causes of hematuria. (merckmanuals.com)

A clinician should determine whether medication adjustment is appropriate.

What Causes Blood Clots in Urine Without Pain?

Painless urinary clots can occur with an enlarged prostate, bladder or kidney tumors, urinary-tract bleeding after a procedure, bleeding disorders, medications, and several other conditions.

The absence of pain does not mean the bleeding is harmless.

Painless visible hematuria is especially important because some urinary-tract tumors initially cause bleeding without significant discomfort.

Other benign conditions can also be painless.

Therefore:

Visible blood or clots without pain still deserve medical evaluation.

This is particularly important when bleeding:

• Returns repeatedly

• Happens in someone over 40–50

• Occurs with a smoking history

• Is associated with unexplained weight loss

• Becomes heavier over time

What Causes Blood Clots in Urine With Pain?

Pain can provide useful clues about the likely cause.

Symptoms With the Blood Clots	Possible Cause to Consider
Burning + frequent urination	UTI/cystitis
Severe side or groin pain	Kidney/ureter stone
Fever + chills + flank pain	Kidney infection
Pelvic pain + urinary urgency	Bladder infection or inflammation
Weak stream + difficulty emptying	Prostate enlargement/obstruction
Severe bladder pressure + unable to urinate	Possible clot retention

These patterns are not definitive diagnoses.

They help determine which tests and evaluations are needed.

What Causes Blood Clots in Urine in Women?

In women, possible causes include:

• Urinary tract infection

• Kidney or bladder stones

• Bladder inflammation

• Kidney or bladder disease

• Urinary-tract tumors

• Medication-related bleeding

• Trauma or procedures

• Urinary tract endometriosis in selected cases

Another important issue is determining whether the blood is actually coming from the urinary tract.

Menstrual or vaginal blood can sometimes contaminate a urine sample and appear to be hematuria.

If blood appears only while menstruating, clinicians may need to distinguish urinary bleeding from vaginal bleeding before determining the cause.

NIDDK includes endometriosis among less common causes of hematuria. (niddk.nih.gov)

What Causes Blood Clots in Urine in Men?

Possible causes in men include:

• Urinary tract infection

• Kidney or bladder stones

• Enlarged prostate

• Prostatitis

• Bladder or kidney tumor

• Prostate-related bleeding

• Recent prostate or urinary procedure

• Trauma

• Anticoagulant use

Older men have a higher likelihood of BPH and certain urinary cancers, so new visible hematuria should not automatically be attributed to aging.

A primary care evaluation can help determine whether further urologic testing is needed.

Can a UTI Cause Blood Clots in Urine?

Yes, a UTI can cause visible urinary bleeding, and significant bladder inflammation may occasionally produce small clots.

A UTI becomes more likely when blood occurs with:

• Burning urination

• Urgency

• Frequency

• Pelvic discomfort

• Cloudy or foul-smelling urine

However, visible blood should not automatically be assumed to be a UTI without appropriate evaluation.

Urinalysis and, when indicated, urine culture can help determine whether infection is present.

Can Kidney Stones Cause Blood Clots in Urine?

Yes. Kidney or ureteral stones can injure urinary-tract tissue and cause gross hematuria.

Stone-related bleeding often occurs with:

• Severe flank pain

• Groin pain

• Waves of pain

• Nausea

• Vomiting

Small amounts of bleeding are common with stones, while heavier bleeding can occasionally result in visible clots.

If pain is severe, urine flow decreases, or fever occurs, urgent medical evaluation is appropriate.

Can Cancer Cause Blood Clots in Urine?

Yes, cancers of the bladder or kidney can cause visible hematuria and sometimes blood clots.

But cancer is not the only explanation.

A person with urinary clots could instead have:

• Infection

• Stones

• Enlarged prostate

• Trauma

• Medication-related bleeding

• Another urinary condition

The important point is not to self-diagnose cancer.

It is to understand that visible unexplained blood needs evaluation because both benign and serious conditions can cause it.

MD Anderson advises evaluation of visible blood even when the amount seems small because an underlying cause still needs to be identified. (mdanderson.org)

Does Red Urine Always Mean Blood?

No. Red or brown urine does not always mean hematuria.

Urine color can change because of:

• Beets

• Certain berries

• Food coloring

• Phenazopyridine

• Rifampin

• Hemoglobin

• Myoglobin

(merckmanuals.com)

A urinalysis can determine whether red blood cells are actually present.

However, visibly passing jelly-like or stringy material is different from simple urine discoloration and warrants medical assessment.

Are Small Blood Clots in Urine an Emergency?

Not every small urinary clot requires the emergency room, but certain patterns can become urgent or life-threatening.

A useful distinction is whether you can still urinate normally and whether there are signs of heavy bleeding, infection, or obstruction.

Situation	Recommended Action
One or two small clots, urinating normally, otherwise well	Arrange prompt medical evaluation
Visible blood occurs once and stops	Still discuss with a clinician
Clots keep increasing	Urgent evaluation
Many or large clots	Urgent/emergency evaluation
Unable to urinate	Emergency care
Severe lower abdominal pressure + little/no urine	Emergency care
Fever and chills with urinary bleeding	Urgent evaluation
Severe flank pain and vomiting	Urgent evaluation
Dizziness, fainting, weakness or heavy bleeding	Emergency care

MD Anderson similarly recommends emergency evaluation when visible urinary bleeding involves several clots, inability to urinate, fever, chills, nausea, vomiting, or other significant symptoms. (mdanderson.org)

What Is Clot Retention?

Clot retention occurs when urinary blood clots become large or numerous enough to block urine from leaving the bladder.

This can cause:

• Inability to urinate

• Severe bladder pressure

• Lower abdominal pain

• Repeated urges to urinate without producing urine

• Worsening bleeding

NIDDK notes that urinary blood clots can block urine flow. (niddk.nih.gov)

Clot retention requires urgent medical treatment.

In some cases, clinicians may need to insert a catheter and irrigate the bladder to remove clots and restore drainage.

This is not something that can be safely treated at home by simply drinking more water.

How Do Doctors Find the Cause of Blood Clots in Urine?

Diagnosis begins with understanding where the bleeding may be coming from and what symptoms accompany it.

Medical History

Your clinician may ask:

• When did the bleeding start?

• Did it happen once or repeatedly?

• Is there pain?

• What color is the urine?

• What do the clots look like?

• How large are they?

• Is there burning or urgency?

• Do you have fever or chills?

• Is there flank or abdominal pain?

• Have you had a recent urinary procedure?

• Do you take blood thinners?

• Do you smoke or have a smoking history?

WebMD’s current guidance specifically recommends noting blood color, clot size and shape, pain location, urinary symptoms, fever, and chills because these details can help guide evaluation. (webmd.com)

Urinalysis

Urinalysis can help confirm:

• Red blood cells

• White blood cells

• Infection markers

• Protein

• Other urinary abnormalities

If a urine test detects blood that cannot be seen with the naked eye, that is microscopic hematuria, which has its own diagnostic pathway.

Urine Culture

When infection is suspected, a urine culture may help determine whether bacteria are present and guide treatment.

Blood Tests

Depending on the situation, clinicians may consider:

• Complete blood count

• Kidney function tests

• Coagulation studies

• Other targeted testing

Imaging

Imaging may be used when stones, tumors, structural abnormalities, or kidney problems are suspected.

Options may include:

• Ultrasound

• CT imaging

• Other specialized imaging depending on the clinical situation

Cystoscopy

A urologist may perform cystoscopy to look directly inside the urethra and bladder with a small camera.

Mayo Clinic includes imaging and cystoscopy among the tests that may be used when evaluating hematuria. (mayoclinic.org)

Not every patient requires every test. The work-up depends on age, symptoms, risk factors, suspected cause, and severity of bleeding.

How Are Blood Clots in Urine Treated?

Treatment focuses on stopping or treating the underlying source of bleeding rather than simply treating the clot itself.

Examples include:

UTI

A confirmed or strongly suspected bacterial UTI may require appropriate antibiotics.

Kidney or Bladder Stones

Treatment depends on:

• Stone size

• Location

• Pain severity

• Urinary obstruction

• Presence of infection

Enlarged Prostate

BPH treatment may include medications or procedures depending on severity.

Tumor or Suspicious Lesion

A urologist may perform further imaging, cystoscopy, biopsy, or cancer-related treatment when indicated.

Medication-Related Bleeding

A clinician may review anticoagulants, antiplatelet medicines, or other drugs.

Do not stop prescribed blood-thinning medication without medical advice.

Clot Retention

If clots are blocking the bladder, urgent catheterization and bladder irrigation may be required to restore urine flow.

Treatment is therefore highly dependent on the cause.

How Manhattan Medical Arts Can Help

Visible blood or clots in urine require an appropriate medical assessment, even when symptoms are mild or painless.

Manhattan Medical Arts can provide an initial evaluation through Primary Care, including medical history, physical examination, urinalysis, and additional testing when clinically appropriate.

For symptoms suggesting a urinary infection, MMA also provides evaluation through its urinary and primary-care services. When kidney stones, urinary obstruction, significant prostate disease, or another structural condition is suspected, further imaging or urology referral may be necessary.

Dr. Syra Hanif, M.D. is a board-certified primary care physician at Manhattan Medical Arts.

The role of primary care is to help determine:

Is the bleeding likely due to infection or another common cause? Is imaging required? Does the patient need urology? Is this urgent enough for emergency care?

For significant bleeding, inability to urinate, severe pain, fainting, or other emergency symptoms, seek emergency medical care rather than waiting for a routine clinic appointment.

Frequently Asked Questions

Final Thoughts

Small blood clots in urine mean that enough blood has entered the urinary tract to coagulate before being passed. Possible causes range from UTIs and stones to enlarged prostate, urinary procedures, bleeding disorders, medications, and cancers of the bladder or kidney.

The most important distinction is that visible clots occur with gross hematuria, not microscopic hematuria. They also are not the same type of blood clot as a DVT or pulmonary embolism.

Symptoms provide useful clues. Burning and frequency suggest infection; severe flank pain can suggest a stone; weak urine flow may point toward prostate or obstruction issues; painless recurrent bleeding can require investigation for structural urinary disease.

Most importantly, seek emergency care if blood clots make it difficult or impossible to urinate, if bleeding becomes heavy, or if you develop severe pain, fainting, fever, chills, or other significant symptoms.

Disclaimer
This blog is for informational & educational purposes only and does not intend to substitute any professional medical advice or consultation. For any health-related concerns, please consult with your physician, or call 911.