Haptoglobin blood test
The haptoglobin blood test measures the level of haptoglobin in your blood.
Haptoglobin is a protein produced by the liver. It attaches to a certain type of hemoglobin in the blood.
How the Test is Performed
A blood sample is needed.
How to Prepare for the Test
Certain medicines may affect the results of this test. Your doctor will tell you if you need to stop taking any medicines. Do not stop any medicine before talking to your doctor.
Drugs that can raise haptoglobin levels include:
Drugs that can lower haptoglobin levels include:
- Birth control pills
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
This test is done to see how fast your red blood cells are destroyed. When red blood cells die, they release hemoglobin.
Haptoglobin attaches to this released hemoglobin, which is also called "free" hemoglobin. Free hemoglobin is not contained within red blood cells. The level of free hemoglobin is usually very low. But it rises when red blood cells are dying.
When the haptoglobin and hemoglobin attach, the new molecule goes to the liver. There, parts of it (such as iron and amino acids) are recycled. The haptoglobin is destroyed.
When red blood cells are actively being destroyed, haptoglobin disappears faster than it is created. Thus, the levels of haptoglobin in the blood drop.
The normal range is 41 - 165 mg/dL (milligrams per deciliter).
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
Higher-than-normal levels may be due to:
- Blockage of the bile tubes (ducts)
- Joint or muscle inflammation, swelling, and pain that comes on suddenly
- Peptic ulcer
- Ulcerative colitis
- Other inflammatory conditions
Lower-than-normal levels may be due to:
- Chronic liver disease
- Collection of blood (hematoma)
- Drug-induced immune hemolytic anemia
- Blood disorder in a fetus or newborn called erythroblastosis fetalis
- Hemolytic anemia due to G6PD deficiency
- Idiopathic autoimmune hemolytic anemia
- Immune hemolytic anemia
- Liver disease
- Transfusion reaction
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Schwartz RS. Autoimmune and intravascular hemolytic anemias In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 163.
Sheehan AM, Yee DL. Resources for the hematologist: interpretive comments and selected reference values for neonatal, pediatric, and adult populations. In: Hoffman R, Benz EJ Jr, Silberstein LE, et al., eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap 164.
Last reviewed 2/24/2014 by Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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