: Haptoglobin, Serum or Plasma, Mass Concentration

: What Is Haptoglobin?

: Haptoglobin is a protein produced primarily by the liver. When red blood cells break down, hemoglobin is released into the bloodstream; haptoglobin binds that free hemoglobin so it can be cleared safely by the body and so the kidneys are protected from damage.

: Why the Test Is Ordered

: Your clinician may order a haptoglobin level when there are signs of increased red blood cell destruction, such as low red blood cell counts with a high reticulocyte count, raised bilirubin, or low or absent haptoglobin. It can also be checked as part of evaluating liver function, inflammation, or certain blood disorders.

: How the Test Is Done

: The test requires a blood sample, usually drawn from a vein in your arm. The sample is sent to the laboratory, where the amount of haptoglobin is measured, often by an immunoassay method. Results are reported as a mass concentration, but the specific units and reference intervals vary by laboratory.

: What the Results May Mean

: A low haptoglobin level can be seen when red blood cells are being broken down faster than the liver can replace the protein, which is a classic sign of hemolysis; that can occur with conditions such as autoimmune hemolytic anemia, transfusion reactions, or certain inherited red blood cell disorders. Haptoglobin can rise with inflammation, infection, or liver disease, so results are interpreted along with other tests and your symptoms. Reference ranges differ between laboratories, so your report's range should be used.