Hemoglobinuria

Alternative names:

urine - hemoglobin

How the test is performed:

Child or adult:
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.

Infant:
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 is a diagnostic tool for hemolytic anemia, or the hemolysis that can result from a transfusion reaction or other process.

Hemoglobin is composed of a molecule called heme, and a protein globin. Together, they form a molecule called hemoglobin, which is within red blood cells and serves as the transfer medium for oxygen and carbon dioxide. In the lungs, the hemoglobin picks up molecules of oxygen. Then, deposited on the red blood cells, the hemoglobin and oxygen are carried 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 and exchanged for oxygen again in a continuous cycle.

Red blood cells have an average life span of 120 days. After this time, they are broken down into their components for reassembly in a new red blood cell. This disassembly typically takes place in the spleen, bone marrow, and liver. If the red blood cells are hemolyzed (broken down) in the vascular system, then the components are free in the blood stream. Free hemoglobin is typically bound by haptoglobins (another protein) and reprocessed. If the level of hemoglobin in the blood rises above the ability of haptoglobin to reclaim it, then hemoglobin begins to appear in the urine.