HPT, hemoglobin-binding protein, Hp
This test measures the level of a protein called haptoglobin in your blood.
Haptoglobin is made by your liver. It binds to a type of hemoglobin that's made when red blood cells die. This haptoglobin-hemoglobin complex is removed from your body by your liver. This leads to a low blood level of haptoglobin. The level of haptoglobin in your blood helps your doctor figure out what type of anemia you have.
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:
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 doctor may also order other blood tests, including:
Your doctor 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 doctor may also order an indirect bilirubin test.
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
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.
For adults, a normal value is 100 to 220 mg/dL.
If your levels are lower, it means you may have hemolytic anemia, in which your red blood cells are prematurely destroyed. Lower levels may also mean that you have a reaction to a blood transfusion or that you have liver disease.
Levels that are higher than normal may mean that you have:
Acute rheumatic disease
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
Certain drugs can affect your results.
You don't need to prepare for this test. But 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 illicit drugs you may use.