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October 7, 1968

Haptoglobin Electrophoresis

Author Affiliations

From the Research Division. Hyland Division Travenol Laboratories, Inc., Los Angeles.

JAMA. 1968;206(2):362-363. doi:10.1001/jama.1968.03150020078015

Haptoglobin is a serum glycoprotein whose name is derived from the Greek work haptein (to fix or seize) because it binds free, circulating hemoglobin to form a very stable complex. Haptoglobin is most probably synthesized in the liver1 and, in complex with hemoglobin, is presumably removed from circulation by the reticuloendothelial system.2 The haptoglobin level determines the renal threshold of hemoglobin. After the haptoglobin binding capacity is exceeded, free hemoglobin appears in the urine. In humans, three types of haptoglobin which occur in genetically controlled combinations are now recognized: type 1-1, with only one hemoglobin-binding fraction; type 2-2, with three to four hemoglobin-binding fractions; and type 2-1, with five to six hemoglobin-binding fractions, one of which has the same electrophoretic mobility as haptoglobin 1-1.3 These correspond to three genotypes produced by a single pair of allelic genes. There are subtypes within group 2-1, and a fourth haptoglobin