An Evaluation of the Methods for Quantitation of Hemoglobin A₂; Results from a Survey of 10,663 Cases

Abstract

Microcolumn chromatography and a new test tube method for quantitation of hemoglobin A₂ were compared with column chromatography on DEAE-Sephadex, starch block and cellulose acetate elec-trophoresis to ascertain their relative accuracy, precision, reproducibility and speed. One hundred seventy-four blood specimens, including 90 samples from genetically proven β-thalassemia hetero-zygotes were examined. The mean Hb A₂ values in normal and β-thal-assemia heterozygotes were: 2.3Z and 4.7%, respectively, determined by microcolumn chromatography; 2.3% and 4.9%, respectively, determined by a new test tube method; 2.5% and 4.6%, respectively, determined by column chromatography on DEAE-Sephadex; 2.6% and 4.8%, respectively, determined by starch block electrophoresis; and 2.4% and 4.8%, respectively, determined by cellulose acetate electrophoresis. Although all five methods were found to be reliable and reproducible, the microcolumn chromatographlc method and the newly developed test tube method using DE-52 cellulose are the most rapid, reproducible, economical, and well suited for large scale surveys.

By microcolumn chromatography, 7,953 school children and 2,710 other cases were screened for the quantity of Hb A₂. In these samples, 578 β-thalassemia heterozygotes were detected.