Hemoglobin is a molecule attached to red blood cells that helps move oxygen and carbon dioxide through the body.

Red blood cells have an average life span of 120 days. After this time, they are broken down into parts that can make a new red blood cell. This typically takes place in the spleen, bone marrow, and liver. If the red blood cells break down the blood vessels, their parts move freely in the bloodstream.

If the level of hemoglobin in the blood rises too high, then hemoglobin begins to appear in the urine. This is called hemoglobinuria.

This article focuses on the urine test done to diagnose hemoglobinuria.

See also:

• Paroxysmal cold hemoglobinuria
• Paroxysmal nocturnal hemoglobinuria

A clean-catch (midstream) urine sample is needed.

Men or boys should first wipe clean the head of the penis. Women or girls need to wash the area between the lips of the vagina with soapy water and rinse well.

As you start to urinate, allow a small amount to fall into the toilet bowl (this clears the urethra of contaminants). Then, in a clean container, catch about 1 to 2 ounces of urine and remove the container from the urine stream. Give the container to the health care provider or assistant.

In infants, thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For boys, the entire penis can be placed in the bag and the adhesive attached to the skin. For girls, the bag is placed over the labia. Place a diaper over the infant (bag and all).

Check your baby frequently and remove the bag after the infant has urinated into it. For active infants, this procedure may take a couple of attempts -- lively infants can displace the bag. The urine is drained into a container for transport back to the health care provider.

No special preparation is necessary for this test. If the collection is being taken from an infant, a couple of extra collection bags may be necessary.

The test involves only normal urination.

This test may be used to help diagnose:

• Hemolytic anemia
• Infections
• The breakdown of red blood cells from a transfusion reaction or other process

Normally, hemoglobin does not appear in the urine.

Hemoglobinuria may be a result of any of the following:

• Acute glomerulonephritis
• Burns
• Crushing injury
• Hemoglobin C disease
• Hemoglobin SC disease
• Hemolytic uremic syndrome (HUS)
• Kidney infection
• Kidney tumor
• Malaria
• Paroxysmal nocturnal hemoglobinuria
• Sickle cell anemia
• Thalassemia
• Thrombotic thromocytic purpura (TTP)
• Transfusion reaction
• Tuberculosis

McPherson RA, Ben-Ezra J, Zhao S. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 27