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Also known as: HPT, Haemoglobin-binding Protein, Hp
Formal name: Haptoglobin
Related tests: FBC; Reticulocyte count; Blood film; Haemoglobin; Haematocrit; Bilirubin; Direct antiglobulin test

At a Glance

Why Get Tested?

To help detect and evaluate haemolytic anaemia

When to Get Tested?

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

Sample Required?

A blood sample taken 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 haemoglobin in the blood. This forms a complex that is rapidly removed from the circulation by the liver and the iron is then recycled. Haemoglobin is a protein 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 haemoglobin is released. When large numbers of RBCs are destroyed, haptoglobin concentrations in the blood will temporarily decrease as the consumption of haptoglobin exceeds that produced by the liver.

Increased RBC destruction may be due to inherited or acquired conditions that cause haemolysis of RBCs. Causes of haemolysis include: transfusion reactions, certain drugs, and/or mechanical breakage, such as may be seen with some artificial heart valves. Acquired haemolysis may also result from dysregulation of the immune system causing the body to destroy its own cells. The destruction may be mild or severe, acute or chronic, and it can lead to haemolytic anaemia. Patients with haemolytic anaemia may experience symptoms such as tiredness, weakness, and shortness of breath and their skin may be pale or jaundiced.

Liver disease  may also result in low haptoglobin levels as liver damage may reduce both the production of haptoglobin and the removal of the haptoglobin-haemoglobin 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

Ask a Laboratory Scientist

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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.