Possible Causes of Blood in the Urine

What You Should Know If You Find Blood in Your Urine

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Discovering blood in the urine (also called hematuria) can be very unsettling. What does blood in your urine mean? What should you do about it?

Where Does the Blood Come From?

Blood in the urine can originate anywhere along the urinary tract. The urinary tract starts at the kidneys and includes the ureters (thin tubes that carry urine to the bladder), the bladder, and the urethra (the tube that carries urine from the bladder out of the body).

Problems at any point along this tract can result in blood in the urine.

What Are the Most Common Causes of Blood in the Urine?

  • Kidney Stones: Kidney stones are formed in the kidneys but can travel into the ureters, the bladder, or the urethra. At any point along the way, the rough (and sometimes jagged) stone can irritate the urinary tract and cause bleeding.
  • Urinary Tract Infections: Urinary tract infections can occur anywhere from the kidneys to the urethra. Infections often result in pain, foul-smelling urine, and possibly fevers and sweats. They can also cause bleeding into the urine.
  • Kidney Disease: Microscopic amounts of blood (only detectable through lab tests) are often found in people with kidney diseases. People with diabetes are particularly prone to developing kidney problems.
  • Injury: A traumatic injury to the kidneys or any other part of the urinary tract can result in blood in the urine. Sports injuries and car accidents are common sources of these injuries.
  • Cancer: Cancer is definitely not the most common causes of hematuria, but it is still a possibility. Cancer involving any part of the urinary tract can cause blood in the urine. Prostate cancer is the most common cancer involving some portion of the urinary tract. The prostate wraps around the upper portion of the urethra in men.
  • Medication: Any medication that thins the blood (including aspirin) can cause hematuria. Certain other drugs that do not directly thin the blood can also cause blood in the urine.
  • Strenuous Activity: While not common, it is possible to develop blood in the urine following intense exercise or other activity.

What Should Be Done About Blood in the Urine?

If you have blood in your urine, go to a doctor to determine if there is a serious cause for the bleeding. As listed above, there are many different reasons for blood in the urine, but ruling out the more serious of these conditions is very important.

Typically, the first doctor you will see is your primary care doctor (such as a family practitioner or internist). They may refer you to a urologist or other doctor for more tests.

After a thorough physical exam, urine tests, and sometimes blood tests and imaging tests (such as ultrasound or CT scan), your doctor will likely be able to determine the cause of your hematuria -- or at least rule out the more serious potential causes.


Wein AJ, Kavoussi LR, Novick AC, et al. Campbell-Walsh Urology 2006.

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