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Also known as: HPT; Hemoglobin-binding Protein; Hp
Formal name: Haptoglobin

At a Glance

Why Get Tested?

To help detect and evaluate hemolytic anemia

When to Get Tested?

When you have signs of anemia such as weakness, paleness, or jaundice that the doctor suspects may be due to red blood cell destruction (hemolytic anemia)

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?


The Test Sample

What is being tested?

This test measures the amount of haptoglobin in the blood. Haptoglobin is a protein produced by the liver. Its purpose is to find and attach itself to free hemoglobin in the blood. This forms a complex that is rapidly cleared out of circulation by the liver for destruction and iron recycling.

Hemoglobin is an iron-containing protein complex that transports oxygen throughout the body. It is normally found inside red blood cells (RBCs); very little is found free, except when RBCs are destroyed and their hemoglobin is released. When large numbers of RBCs are destroyed, haptoglobin concentrations in the blood will temporarily decrease as the rapid consumption of haptoglobin exceeds production by the liver.

Increased RBC destruction may be due to inherited or acquired conditions that cause hemolysis of RBCs, transfusion reactions, certain drugs, and/or mechanical breakage, such as may be seen with some prosthetic heart valves. The destruction may be mild or severe, acute or chronic, and it can lead to hemolytic anemia. People with hemolytic anemia may experience symptoms such as fatigue, weakness, and shortness of breath and their skin may be pale or jaundiced.

Liver disease may also result in decreased haptoglobin concentrations as liver damage may inhibit both the production of haptoglobin and the clearing of the haptoglobin-free hemoglobin complexes.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Gersten, T. (Updated 2012 February 8). Haptoglobin. MedlinePlus Medical Encyclopedia. [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003634.htm. Accessed August 2012.

(© 1995–2012). Haptoglobin, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/9168 through http://www.mayomedicallaboratories.com. Accessed August 2012.

Lichtin, A. (Revised 2009 February). Overview of Hemolytic Anemia. Merck Manual for Healthcare Professionals [On-line information]. Available online through http://www.merckmanuals.com. Accessed August 2012.

(2011 April 1). What is Hemolytic Anemia? National Heart Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/health/health-topics/topics/ha/ through http://www.nhlbi.nih.gov. Accessed August 2012.

Schick, P. (Updated 2011 August 8). Hemolytic Anemia. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/201066-overview through http://emedicine.medscape.com. Accessed August 2012.

(2008 November). Haptoglobin (HP) Genotyping. ARUP Laboratories Technical Bulletin [On-line information]. Available online through https://www.aruplab.com. Accessed August 2012.

Cook, J. et. al. (Updated 2011 July). Hemolytic Anemias. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/HemolyticAnemias.html?client_ID=LTD#tabs=0 through http://www.arupconsult.com. Accessed August 2012.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO. Pp 466-467.

(© 2005). Haptoglobin. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.aruplab.com/guides/clt/tests/clt_291a.jsp#4273706 through http://www.aruplab.com/.

Dhaliwal, G. et. al. (2004 June 1). Hemolytic Anemia. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20040601/2599.html through http://www.aafp.org.

Nanda, R., Updated (2005 February 1). Haptoglobin. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003634.htm.

(© 1995-2005). Autoimmune Hemolytic Anemia. Merck Manual-Second Home Edition [On-line information]. Available online at http://www.merck.com/mmhe/sec14/ch172/ch172f.html?qt=haptoglobin&alt=sh through http://www.merck.com.

O-Hara Paggen, M. (1999 September 1). HELLP Syndrome: Recognition and Perinatal Management. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/990901ap/829.html through http://www.aafp.org.

Sibai, B. (2004 May). Diagnosis, Controversies, and Management of the Syndrome of Hemolysis, Elevated Liver Enzymes, and Low Platelet Count. ACOG, High-Risk Pregnancy Series: An Expert's View v 103 (5 part 1). [On-line journal]. Available online at http://www.mccn.edu/library/ABOG/2005/PMID15121574.pdf#search='test%20haptoglobin' through http://www.mccn.edu.

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pp 199.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 512-513.

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition]. Pp 840.

Levin, M. (2007 March 8). Haptoglobin. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003634.htm . Accessed on 11/23/08.

(2006 September). What is Hemolytic Anemia? National Heart Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/health/dci/Diseases/ha/ha_whatis.html through http://www.nhlbi.nih.gov. Accessed on 11/23/08.

Schick, P. (2007 January 29). Hemolytic Anemia. eMedicine [On-line information]. Available online at http://www.emedicine.com/med/TOPIC979.HTM through http://www.emedicine.com. Accessed on 11/23/08.