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What causes blood in urine? 47 possible conditions

What Is Hematuria?

Hematuria is the medical term for blood in your urine. Several different conditions and diseases can cause hematuria. These include infections, kidney disease, cancer, and rare blood disorders. The blood may be visible or in such small quantities that it can’t be seen with the naked eye. Any blood in the urine should be treated as serious—even if it happens only once. You should make a doctor’s appointment as soon as possible. Ignoring hematuria can lead to the worsening of very serious conditions like cancer and kidney disease. Your doctor can analyze your urine and order imaging tests to determine the cause of the hematuria. He or she can then treat that cause.

Types of Hematuria

Hematuria may be gross or microscopic.

Gross Hematuria

If there is enough blood in your urine that your urine appears pink or red or has spots of visible blood, you have gross hematuria.

Microscopic Hematuria

When you cannot see the blood because the amount is so small, you have microscopic hematuria. Microscopic hematuria can only be confirmed with a lab test that detects blood or by looking at a sample of urine under a microscope.

Causes of Blood in the Urine

There are many possibilities for hematuria. In some cases, the blood may actually be from a different source. Blood can appear to be in the urine when it is really coming from the vagina in women, the ejaculate in men, or from a bowel movement in men and women. If the blood is truly in your urine, there are several potential causes.


Infection is one of the most common causes of hematuria. The infection could be somewhere in your urinary tract, your bladder, or in your kidneys. Infection occurs when bacteria moves up the urethra, the tube that carries urine out of the body from the bladder. The infection can move into the bladder and even into the kidneys. It often causes pain and a need to urinate frequently. There may be gross or microscopic hematuria.


Another common reason for blood in the urine is the presence of stones in the bladder or kidney. These are crystals that form from the minerals in your urine. They can develop inside your kidneys or bladder. If the stones are large, they can cause a blockage that often results in hematuria and significant pain.

Enlarged Prostate

In men middle-aged and older, a fairly common cause of hematuria is an enlarged prostate. This gland is just beneath the bladder and near the urethra. When the prostate gets bigger, as it often does in men at middle age, it compresses the urethra. This causes problems with urinating and may result in blood in the urine.

Kidney Disease

A less common reason for seeing blood in the urine is kidney disease. The kidneys can become diseased and inflamed, causing hematuria. This disease can occur on its own or as part of another disease such as diabetes.

In children aged six to 10, the kidney disorder poststreptococcal glomerulonephritis, which can follow an untreated strep throat infection, may cause hematuria. This disorder can develop one to two weeks after an untreated strep infection. Once common, it is rare today because strep infections can be quickly treated with antibiotics.


Cancer of the bladder, kidney, or prostate can cause blood in the urine. Unfortunately, this is a symptom that often occurs once the cancer is already advanced. There may not be earlier signs of a problem.


Certain medicines can cause hematuria. These include penicillin, aspirin, blood thinners like heparin and warfarin, and a cancer drug called cyclophosphamide.

Less Common Causes

There are a few other causes of hematuria that are not very common. Rare blood disorders such as sickle cell anemia, Alport syndrome, and hemophilia can cause blood in the urine. Strenuous exercise or a blow to the kidneys can also cause blood to show up in the urine.

When to Seek Medical Help

Because some of the causes of blood in the urine are very serious, you should seek medical attention the first time you see it. Even a small amount of blood in your urine should not be ignored. If you do not see blood in your urine but experience frequent, difficult, or painful urination, abdominal pain, or kidney pain, see a doctor. These may all be indications of microscopic hematuria.

Seek emergency help if you cannot urinate, if you see blood clots when you urinate, or if blood in your urine is accompanied by nausea, vomiting, fever, chills, and pain in your side, back, or abdomen.

Consequences of Ignoring Hematuria

Many of the causes of blood in the urine are very serious, and ignoring this symptom can have dire consequences. If the blood is from cancer, ignoring it can lead to an advancement of the tumors to the point that they are no longer treatable. Infections that are not treated can ultimately lead to kidney failure.

If the cause of hematuria is an enlarged prostate, treatment can help reduce symptoms. Ignoring it may lead to discomfort from needing to urinate frequently, severe pain, and even cancer. Ignoring hematuria when you have stones can be very painful. Stones must be passed, but this can be helped along by prescription medications and treatments to break them into smaller pieces.

What to Expect During a Doctor’s Appointment

If you are seeing your doctor for hematuria, there are many questions you will need to answer. Your doctor will ask you about the amount of blood and when you see it during the course of urination. He or she will want to know about your frequency of urination, any pain you are experiencing, if you see blood clots, and what medications you are taking.

Your doctor will then give you a physical examination and collect a sample of your urine for testing. The analysis of your urine can confirm the presence of blood and detect bacteria if an infection is the cause. If no bacteria are found, your doctor may order imaging tests such as a computerized tomography or CT scan, which uses radiation to image your body.

Another possible test your doctor may want to do is a cystoscopy. This involves using a small tube to send a camera up your urethra and into your bladder. With the camera, your doctor can examine the interior of your bladder and urethra to determine a cause of your hematuria.

Prevention of Hematuria

Preventing hematuria means preventing the underlying causes. To prevent infections, drink plenty of water daily, urinate immediately after sexual intercourse, and practice good hygiene. To prevent stones, drink plenty of water and avoid excess salt and certain foods like spinach and rhubarb. To prevent bladder cancer, do not smoke, limit your exposure to chemicals, and drink plenty of water.

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See a list of possible causes in order from the most common to the least.


Kidney Stones

Kidney stones are solid masses of crystalized calcium or other substances that originate in the kidneys but can pass through the urinary tract. The greatest risk factor is making less than one liter of urine per day.

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Obstructive Uropathy

Obstructive uropathy is a condition in which your urine flow is blocked, and backs up into the kidneys. IIt may be caused by a blockage in one of the ureters.

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Benign Enlargement of Prostate

Benign enlargement of the prostate, or benign prostatic hyperplasia, is a common condition where the prostate gland swells beyond normal size. It is a normal condition of male aging but can interfere with urination.

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Urinary Tract Infection

UTIs are usually caused by bacteria and can occur in any part of the urinary tract. Symptoms of upper UTIs include pain in the upper back, chills, fever, and nausea.

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Urethritis is an infection of the urethra, the tube that carries urine from the bladder and semen out of the body. Symptoms include burning while urinating, abdominal pain, and discharge.

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Pyelonephritis is an inflammation of the kidney and upper urinary tract. Symptoms include flushed skin, back pain, fever, and nausea.

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Bladder Stones: The Bad, the Ugly, and the Good

Bladder stones are crystals that form when concentrated urine is left in the bladder after urination, often due to dehydration or being unable to empty the bladder totally. Symptoms include painful urination and others.

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Bladder Cancer

Bladder cancer occurs in the tissues of the bladder, which is the organ that holds urine. Fatigue, weight loss, painful or frequent urination, and abdominal or back pain are symptoms.

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Polycystic Kidney Disease

Polycystic kidney disease (PKD) is an inherited kidney disorder that causes fluid-filled cysts to form in the kidneys. Abdominal and back pain, easy bruising, and fatigue are possible signs.

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Prostate Cancer Overview

Learn prostate cancer information, causes, symptoms and treatments.

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Urethral Stricture

Usually the urethra is wide enough for urine to flow freely through it. When it narrows, it can restrict urinary flow. This is known as a urethral stricture.

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Cystitis is inflammation of the bladder. It's most often caused by a bacterial infection known as a urinary tract infection (UTI). It can become a serious health issue if the infection spreads to the kidney.

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Acute Unilateral Obstructive Uropathy

Obstructive uropathy is a blockage that prevents urine from leaving your kidneys. When this condition develops suddenly and only affects one kidney, it’s called acute unilateral obstructive uropathy. The blockag...

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Cervical Dysplasia

Cervical dysplasia is a condition in which healthy cells on the cervix undergo some abnormal changes. The cervix is the lower part of the uterus that leads into the vagina. It is the cervix that dilates durin...

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Acute Prostatitis

Acute prostatitis is the sudden onset of inflammation in the prostate. The prostate gland is a small, walnut-shaped organ located at the base of the bladder, in front of the rectum. The prostate provides 70 percent o...

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ABO Incompatability Reaction

This condition is considered a medical emergency. Urgent care may be required.

An ABO incompatibility reaction can occur if you receive the wrong type of blood during a blood transfusion. It's rare but serious and potentially fatal.

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Reactive Arthritis (Reiter's Syndrome)

Reiter's syndrome produces inflammation, swelling, and pain in the joints due to infection elsewhere in the body. Symptoms include mouth ulcers, painful urination, and urethral discharge.

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Lupus Nephritis

Systemic lupus erythematosus (SLE, or, more commonly "lupus") is a condition in which your immune system begins attacking different areas of your body. Lupus nephritis is one of the most serious complications of lupus...

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Goodpasture syndrome

Goodpasture syndrome is a rare and potentially life-threatening autoimmune disease. It occurs when the immune system attacks the walls of the lungs and the tiny filtering units in the kidneys. The disorder is name...

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Rhabdomyolysis is breakdown of muscle fibers. Muscle breakdown causes the release of myoglobin into the bloodstream. Myoglobin can cause kidney damage. Symptoms include dark urine, muscle weakness, and fatigue. Abou...

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This feature is for informational purposes only and should not be used to diagnose.
Please consult a healthcare professional if you have health concerns.