HAPTOGLOBIN

CLINICAL UTILITY:

Haptoglobin (free form) is a alpha-2-globulin with three phenotypes (Hp 1-1, Hp2-1, Hp 2-2) having a mean molecular weight of 100,000. It produced by the liver. In circulation, haptoglobin binds to hemoglobin irreversibly and stoichiometrically. Once bound, the haptoglobin-hemoglobin complexes are rapidly removed from the circulation by the liver cells. The half life of the haptoglobin-hemoglobin complex is ~8 minutes. Haptoglobin transports hemoglobin (released during erythrocyte senescence) to the reticuloendothelial system (liver, bone marrow, spleen), where further hemoglobin degradation occurs, allowing reutilization if iron during bone marrow erythropoisis. Decreased haptoglobin has been reported in hemolytic disease, megaloblastic anemia and hemolytic transfusion reaction. Congenital defects that influence erythrocyte stability (sickle cell disease and other hemoglobinopathies, glucose-6-phosphate dehydrogenase deficiency, hereditary spherocytosis, thalassemia and related disorders may result in significant intravascular hemolysis with the consequent depletion of haptoglobin. The congenital absence of haptoglobin (anhaptoglobinemia) has been encountered in rare instances. Haptoglobin, acting as an acute-phase protein, may be elevated in bacterial and viral infection, tumors associated with necrosis and inflammation, and myocardial infarction.

METHOD DESCRIPTION:

Haptoglobin in this assay is measured in a nephelometric method

REFERENCE RANGE:

100 - 300 mg/dL

SPECIMEN REQUIREMENTS:

Serum (1.0 ml, 0.5 ml minimum) is the recommended sample type.