Haptoglobin

Does this test have other names?

HPT, hemoglobin-binding protein, Hp

What is this test?

This test measures the level of a protein in your blood called haptoglobin.

Haptoglobin is made by your liver. It binds to a type of hemoglobin that's made when red blood cells die, leading to anemia. Hemoglobin is a protein in your red blood cells that carries oxygen from your lungs to the rest of your body. The haptoglobin-hemoglobin complex is removed from your body by your liver. If too much hemoglobin is bound to haptoglobin, the levels of haptoglobin will drop. The level of haptoglobin in your blood helps your doctor figure out what type of anemia you have.

Why do I need this test?

You may have this test if your doctor suspects that you have anemia, or a low number of red blood cells. Symptoms of anemia include:

• Weakness.

• Tiredness.

• Pale skin.

• Shortness of breath.

• Jaundice, or a yellow tinge to your skin and the whites of your eyes.

• Dark-colored urine.

You may also have this test if you have symptoms of liver disease.

What other tests might I have along with this test?

Your doctor may also order other blood tests, including:

• Reticulocyte count.

• Blood smear.

• Hemoglobin.

• Hematocrit.

Your doctor may also order a direct antiglobulin test if you have had a blood transfusion and they suspect that you are reacting to the transfusion. Your doctor may also order tests for indirect bilirubin and lactate dehydrogenase (LDH).

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your doctor what your test results mean for you.

Results are given in milligrams per deciliter (mg/dL). Normal results depend on your age and gender, other diseases or conditions you have, and the method the lab uses to analyze the test.

In general, a normal value for adults is 40 to 200 mg/dL.

If your levels are lower, it means you may have hemolytic anemia, in which your red blood cells are prematurely destroyed. An undetectable level is almost always due to hemolytic anemia. Lower levels could also mean that you have had a reaction to a blood transfusion or that you have liver disease or infectious mononucleosis.

Haptoglobin is considered an “acute-phase” protein. This means that it will be elevated in many inflammatory diseases. Levels that are higher than normal may mean that you:

• Have acute rheumatic disease.

• Have had a heart attack.

• Have ulcerative colitis.

• Have an ongoing infection.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect my test results?

Certain medicines can affect your results. These include androgens (a type of hormone), corticosteroids, and birth control pills.

How do I get ready for this test?

You don't need to prepare for this test. Be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.