Haptoglobin (HP) Test

This test measures the amount of haptoglobin in your blood. Haptoglobin is a protein made by your liver to get rid of the hemoglobin outside your red blood cells. Hemoglobin is a protein in your red blood cells that carries oxygen from your lungs to the rest of your body.

Most hemoglobin is found inside your red blood cells. When red blood cells die, they release hemoglobin. This results in small amounts of hemoglobin circulating in your bloodstream.

Haptoglobin binds to the hemoglobin in your bloodstream, and then your liver removes it from the body. Damaged red blood cells also release hemoglobin. So if your red blood cells are damaged or break down faster than usual, you will have more hemoglobin than usual in your bloodstream.

That means haptoglobin will bind to all of this extra hemoglobin so that it can be cleared from your body. The haptoglobin may leave the body faster than your liver can make it. This causes your haptoglobin blood levels to drop.

If your haptoglobin levels are too low, it may be a sign of a disorder of the red blood cells, such as anemia.

Why this test is done

You may need this test if you have symptoms of hemolytic anemia or another blood disorder. These may include:

• Weakness or fatigue
• Pale skin
• Shortness of breath
• Headache
• Dizziness
• Arrhythmia (a problem with the rate or rhythm of your heartbeat)
• Jaundice, a condition that causes your skin and eyes to turn yellow
• Dark colored urine

You may also need this test if you've had a blood transfusion. A haptoglobin test may be done along with another test called direct anti-globulin. The results of these tests can show if you've had a bad reaction to the transfusion.

How to prepare

You don't need any special preparations for a haptoglobin test.

Sample type

Blood

Other names for this test

hemoglobin-binding protein, HPT, Hp