Blood in the Urine Overview
ساعت ٤:٤٥ ‎ب.ظ روز یکشنبه ٢٥ بهمن ۱۳۸۸  کلمات کلیدی:

Blood in the Urine Overview


Blood in the urine is a common problem. The medical term for red blood cells in the urine is 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 provider should blood in the urine be attributed to a non-serious cause.

The urinary tract consists of the following structures:

  • 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 thebladder.


  • 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

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.

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 is normal. The average person with a healthy urinary tract excretes about 1 million red blood cells (RBC) in the urine each day. This amount of blood is not visible. This is not considered to be hematuria.

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 hematuria. About 3% of people develop gross hematuria.

  • Women develop hematuria more than men because women are more likely to have urinary tract infections.


  • 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, have enlargement of the prostate, or cancer.