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Haptoglobin

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Also known as: HPT; Hemoglobin-binding Protein; Hp
Formal name: Haptoglobin

The Test Sample

What is being tested?

This test measures the amount of haptoglobin in the blood. Haptoglobin is a protein produced by the liver. Its purpose is to find and attach itself to free hemoglobin in the blood. This forms a complex that is rapidly cleared out of circulation by the liver for destruction and iron recycling.

Hemoglobin is an iron-containing protein complex that transports oxygen throughout the body. It is normally found inside red blood cells (RBCs); very little is found free, except when RBCs are destroyed and their hemoglobin is released. When large numbers of RBCs are destroyed, haptoglobin concentrations in the blood will temporarily decrease as the rapid consumption of haptoglobin exceeds production by the liver.

Increased RBC destruction may be due to inherited or acquired conditions that cause hemolysis of RBCs, transfusion reactions, certain drugs, and/or mechanical breakage, such as may be seen with some prosthetic heart valves. The destruction may be mild or severe, acute or chronic, and it can lead to hemolytic anemia. People with hemolytic anemia may experience symptoms such as fatigue, weakness, and shortness of breath and their skin may be pale or jaundiced.

Liver disease may also result in decreased haptoglobin concentrations as liver damage may inhibit both the production of haptoglobin and the clearing of the haptoglobin-free hemoglobin complexes.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.