Haptoglobin (HP) Test
Reviewed
Also called: Hemoglobin-binding protein, HPT, Hp
This test measures the amount of haptoglobin in your blood. Haptoglobin is a protein made by your liver to remove hemoglobin from your bloodstream. When red blood cells are damaged or break down faster than usual, haptoglobin levels drop.
Specimen: Blood
Why this test may be ordered
- To diagnose hemolytic anemia
- To see if another type of anemia or blood disorder is causing symptoms
- To check for a reaction to a blood transfusion
Preparation and collection
You don't need any special preparations for a haptoglobin test.
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. This usually takes less than five minutes.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
This test measures the amount of haptoglobin in your blood. Haptoglobin is a protein made by your liver to remove hemoglobin from your bloodstream. When red blood cells are damaged or break down faster than usual, haptoglobin levels drop.
- Lower than normal: Lower than normal haptoglobin level suggests that red blood cells are being destroyed faster than they can be replaced. Limitation: A low haptoglobin level is normal for infants less than six months old. Certain medicines may cause test results to be higher or lower than normal. Severe blood loss and conditions that worsen kidney function may also affect haptoglobin level results. Next step: Low levels may indicate hemolytic anemia, liver disease, or a reaction to a blood transfusion. Your provider will consider your symptoms, medical history, and the results of other blood tests to understand the results.
- Higher than normal: Higher than normal haptoglobin level may indicate an inflammatory condition or other health issue. Limitation: High haptoglobin levels may be a sign of an inflammatory disease, but haptoglobin testing is not usually used to diagnose or monitor conditions related to high levels. Certain medicines may cause test results to be higher or lower than normal. Severe blood loss and conditions that worsen kidney function may also affect haptoglobin level results. Next step: High levels may indicate ulcerative colitis, acute rheumatic disease, severe infection, or diabetes. Your provider will consider your symptoms, medical history, and the results of other blood tests to understand the results.
- A low haptoglobin level is normal for infants less than six months old.
- Certain medicines may cause test results to be higher or lower than normal.
- Severe blood loss and conditions that worsen kidney function may also affect haptoglobin level results.
- High haptoglobin levels may be a sign of an inflammatory disease, but haptoglobin testing is not usually used to diagnose or monitor conditions related to high haptoglobin levels.
What to do next
Your provider will consider your symptoms, medical history, and the results of other blood tests to understand the results. Other blood tests that may be ordered include: reticulocyte count, hemoglobin test, hematocrit test, lactate dehydrogenase test, blood smear, and complete blood count. If you have questions about your results, talk to your provider.
- What is a haptoglobin test used for?
- What do the results mean?
- Is there anything else I need to know?