Urine - hemoglobin

Alternative names

Hemoglobinuria

Definition

Hemoglobin is a molecule attached to red blood cells in the blood. Normally, unbound hemoglobin is not excreted in the urine. Hemoglobinuria is the presence of free, unbound hemoglobin in the urine, which is not normal.

How the test is performed

You need to collect a "clean-catch" (midstream) urine sample. To obtain a "clean-catch" sample, men or boys should 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.

For 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 males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, 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, causing an inability to obtain the specimen. The urine is drained into a container for transport back to the health care provider.

How to prepare for the test

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.

How the test will feel

The test involves only normal urination.

Why the test is performed

This test may be used to help diagnose:

• hemolytic anemia
  
• infections
  
• the breakdown of red blood cells from a transfusion reaction or other process
  

Hemoglobin is composed of a molecule called heme, and a protein called globin. Together, they form a molecule called hemoglobin, which is within red blood cells. The purpose of hemoglobin is to transfer oxygen and carbon dioxide.

In the lungs, the hemoglobin picks up molecules of oxygen. Then, the hemoglobin and oxygen are carried within red blood cells to tissues that need oxygen. The hemoglobin gives up the oxygen and picks up carbon dioxide from the tissue - which is then carried back to the lungs again in a continuous cycle.