Blood in the Urine

Blood in the Urine Summary
Blood in the urine is called hematuria. Hematuria may be caused by infection, inflammation, or injury to the urinary system. Treatment of hematuria depends upon the underlying cause of the bleeding.
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Blood in the Urine Overview

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Blood in the urine is a common problem. The medical term for red blood cells in the urine is hematuria. If there are only a small number of red blood cells in the urine, the urine color might not change and the blood cells are only apparent under a microscope. This is usually referred to a microscopic hematuria. Larger amounts of blood in the urine can cause a discoloration of the urine from a light pinkish hue to a dark red or even brown appearance. This is known as gross hematuria or macroscopic hematuria. Sometimes blood in the urine is a sign of a serious problem in the urinary tract, while other times it is not serious and requires no treatment. Only after a thorough evaluation by a health care professional should blood in the urine be attributed to a nonserious cause.

  • Kidneys: You have two kidneys, located closer to your back than your front at about waist level. The kidneys filter the blood in your body and produce urine.
  • Ureters: These narrow, hollow tubes carry urine from the kidneys to the bladder.
  • Bladder: The bladder is a balloon-like organ that holds urine until it is convenient for you to empty your bladder (urinate).
  • Urethra: This narrow, hollow tube carries urine from the bladder to the outside of your body. The flow of urine is controlled by internal and external sphincter muscles, which tighten or relax around the urethra, holding or releasing urine.
  • In men, the genitals and prostate are considered part of the urinary system. The prostate surrounds the urethra in men. It is made up of glands that secrete a fluid that is part of semen. The prostate often becomes enlarged in older men.
Picture of the urinary system.
Picture of the urinary system.

Blood in the urine is not always visible. If the amount of blood is small, the urine can look normal. This is called microscopic hematuria because the blood cells are visible only under a microscope. Typically, this is discovered when the patient has a urine test for some other reason or as part of a screening examination.

When there is enough blood to be visible, the urine may look pinkish, red, or smoky brown (like tea or cola). This is called gross or frank hematuria. It takes very little blood in urine to be visible -- about 1/5 of a teaspoon in a half quart of urine.

A trace amount of blood in your urine can be normal but needs to be observed and followed by a health care professional.

An abnormal amount of blood in the urine can be acute (new, occurring suddenly) or chronic (ongoing, long term). Acute hematuria can occur just once, or it can occur many times.

Sometimes the urine can appear with a color, indicating hematuria, though the urine actually does not contain red blood cells but rather is discolored by medications or foods. This can be distinguished by a urinalysis (UA) test.

Up to 10% of people have at least one episode of hematuria. About 3% of people develop gross hematuria.

  • Women develop hematuria more than men because women are more likely to have urinary tract infections, and these infections may lead to hematuria.
  • Older adults, especially men, have hematuria more often than younger people because they are more likely to take medications that can irritate the urinary tract, or have enlargement of the prostate, or cancer.
Medically Reviewed by a Doctor on 6/28/2013

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