What Causes Blood in Urine (Hematuria)?

Blood in your urine can be a sign of various medical conditions, in particular those affecting the kidneys, bladder, urinary tract, or prostate.

It’s natural to feel concerned if you notice blood in your urine. Visible blood in your urine is known as gross hematuria. Blood in your urine that can’t be seen and can be detected only with a microscope is known as microscopic hematuria. (1)

If your urine is pink, red, or brown, you may be experiencing hematuria. A small amount of blood can change the color of your urine, but you may also notice that you’re passing larger blood clots. (2) 

Discolored urine, however, does not mean that you have blood in your urine. Certain foods such as blackberries, rhubarb, and beets, as well as some medications and vitamins, can change the color of your urine. (3) 

Regardless, it’s best to consult your doctor anytime that your urine is discolored to determine whether the change is harmless or more serious.

Additional symptoms that might accompany blood in urine can include: (4)

• Discomfort or pain while urinating
• Urgent need to urinate
• Frequent need to urinate
• Weight loss
• Inability to urinate
• Fever
• Nausea or vomiting
• Abdominal pain
• Chills

When you experience hematuria, red blood cells leak from your kidneys or your urinary tract into your urine. Blood in your urine is not always a sign of a serious medical condition, but it should be taken as a warning sign that something could be wrong. Hematuria can be a sign of many different medical conditions, including: (2)

• Bladder or kidney stones
• Kidney disease
• Kidney injury
• Enlarged prostate
• Urinary tract infections
• Blood clots
• Kidney infections
• Cancer of kidneys, bladder, or urethra
• Sickle cell anemia

If you notice blood at the beginning of urination, the origin of the bleeding could be the urethra. If you notice blood throughout urination, it’s possible that the origin is your bladder, kidneys, or ureters. If you notice blood at the end of a urination stream, the cause may be the bladder or prostate. (5)

If you’re over age 35 and are a smoker, blood in your urine is often a sign of bladder cancer. (5)

Certain medications can also cause urinary bleeding, including: (2)

• cyclophosphamide (Cytoxan)
• penicillin
• aspirin
• heparin
• Anticoagulants such as warfarin (Coumadin), rivaroxaban (Xarelto), dabigatran (Pradaxa), or apixaban (Eliquis)

Extreme exercise can also cause hematuria, possibly because it can cause bladder trauma, dehydration, or the breaking down of red blood cells. If you’re a runner, or have exercised strenuously, and notice blood in your urine, contact your doctor. (2)

Blood may also come from other sources, such as the vagina during menstruation, ejaculation in men (often because of a prostate problem), or a bowel movement due to hemorrhoids or other issues. (4)

Urinary tract infections, kidney stones, and prostate problems are common causes of small blood clots, which can sometimes look like coffee grounds. If you notice blood clots in your urine — even small ones — you should contact your doctor. Larger blood clots can block the flow of urine and cause discomfort, and they’re often a sign of a medical emergency. (6)

If you notice different shapes of blood clots in your urine, such as a wormlike form, it may be a sign that you are experiencing bleeding from the urethra or prostate. If the clots are painful, they might be coming from the tubes that connect your kidneys to your bladder, known as ureters. (5)

Can Dehydration Cause Blood in Urine?  

While dehydration is less likely to be a direct cause of blood in the urine, it can lead to conditions that can cause hematuria. For example, low urine volume due to consistent dehydration can lead to kidney stones that can cause blood in the urine. Dehydration may also be a contributor when extreme exercise causes blood in the urine. (7)

Both visible and microscopic blood in the urine of children can be a sign of a medical condition or risk of developing a medical condition.

If a red, pink, or brown color is visible, the change is likely due to medication or eating certain foods. Regardless, parents should consult a doctor if they notice any abnormal color changes in their child’s urine. (8)

Roughly 3 to 4 percent of children will experience microscopic blood in their urine. Because microscopic blood isn’t visible, parents should also look for these signs: (8)

• Puffiness around the eyes
• Swelling of hands and feet
• Abdominal or groin pain
• Low urine output
• Wetting accidents
• Increased frequency of urination
• Pain while urinating

Hematuria in children can be a sign of: (9)

• Polycystic kidney disease
• Kidney stones
• Hereditary nephritis
• Alport syndrome
• Sickle cell disease
• Kidney cysts

It’s also possible that your child has benign familial hematuria, which could mean that there is nothing medically wrong with your child.

To determine the cause of blood in urine, your doctor will usually begin by discussing your medical history with you. They may ask if you’ve had any recent infections or have a family history of hematuria. (2) You can prepare for your appointment by making a few notes about the color and odor of your urine, as well as how frequently you’ve been urinating and whether you experience any pain while urinating. You may want to take a photo of your discolored urine on your mobile phone that you can show to your doctor during your appointment.

Your doctor may also perform a number of tests. A urinalysis can detect microscopic hematuria and also test for a urinary tract infection or kidney stones. If a urinalysis does not determine the cause, your doctor may also perform a CT scan, an MRI, or an ultrasound. They may also want to examine the bladder and urethra via cystoscopy, where a tube with a camera attached is inserted into your bladder. (2) Additional tests may include: (4)

• Antinuclear antibody test
• Blood creatinine level
• Kidney biopsy
• Complete blood count (CBC)
• Strep test
• Blood disorder tests
• Coagulation tests
• Blood chemistry tests
• 24-hour urine collection

“Many doctors and patients underestimate the importance of searching for a cause for blood in the urine,” says Anne Schuckman, MD, associate professor of urology and urologic oncology at the Keck School of Medicine of USC in Los Angeles. She recommends that patients with hematuria receive both a CT scan and a cystoscopy. “Unfortunately, many patients who have blood in the urine may also have some white cells in the urine and are treated for a presumed urinary tract infection. The antibiotics may help for a while. However, a serious underlying reason for the blood can be missed without a full investigation.”

Treatment for blood in urine will depend on what medical condition is causing the hematuria. For example, if you have a urinary tract infection, your doctor may prescribe antibiotics. If you have an enlarged prostate, your doctor may prescribe medication to shrink it. (2)

For bladder or kidney stones, your doctor may use shock wave treatment, known as extracorporeal shock wave lithotripsy. They may remove the stone by inserting a scope through the urethra, or they may recommend surgery. (7)