Reference range of serum haptoglobin is haptoglobin phenotype-dependent inblacks

Reference values for serum haptoglobin (Hp), were established in a Black Zi mbabwean population. The upper limit (2.15 g/l) is comparable to the one in Caucasians, but the lower limit (0.12 g/l) is much lower than the proposed interim international reference limit (03 g/l). Subjects that typed as Hp 0-0 by starch gel electrophoresis technique were retyped using high perform ance gel permeation chromatography. This resulted in a 32% decrease in the Frequency of Hp 0-0, but an increase in Hp 2-2 and Hp 2-1M phenotype freque ncies. In the Zimbabwean Blacks, the Hp 0-0 Frequency was estimated to be 2 .9%. Haptoglobin reference values were found to be Hp phenotype-dependent; highest values were found in Hp 1-1 (median 0.88 g/l; range 0.31-1.69 g/l) and in Hp 2-1 (median 0.90 g/l; range 0.31-2.22 g/l) and lower values (medi an 0.66 g/l; range 0.13-1.79 g/l) in Hp 2-2 subjects. The Hp 2-1M phenotype was characterized by low reference values (0.18-1.25 g/l) (P < 0.05), In t hree cases of the rare variant Hp Johnson, high Hp concentrations were foun d (median 1.57 g/l; range 0.98-1.57 g/l). (C) 2000 Elsevier Science B.V. Al l rights reserved.