HPT, hemoglobin-binding protein, Hp
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. This 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 healthcare provider figure out what type of anemia you have.
You may have this test if your healthcare provider suspects that you have anemia, or a low number of red blood cells. Symptoms of anemia include:
Shortness of breath
Jaundice, or a yellow tinge to your skin and the whites of your eyes
You may also have this test if you have symptoms of liver disease.
Your healthcare provider may also order other blood tests, including:
Your healthcare provider may also order a direct antiglobulin test if you have had a blood transfusion and he or she suspects that you are reacting to the transfusion. Your healthcare provider may also order tests for indirect bilirubin and lactate dehydrogenase (LDH).
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider 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.
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
The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.
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.
Certain medicines can affect your results. These include androgens (a type of hormone) and corticosteroids.
You don't need to prepare for this test. Be sure your healthcare provider 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.