An evaluation of the methods for quantitation of hemoglobin A2: results from a survey of 10,663 cases.

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 electrophoresis to ascertain their relative accuracy, precision, reproducibility and speed. One hundred seventy-four blood specimens, including 90 samples from genetically proven beta-thalassemia heterozygotes were examined. The mean Hb A2 values in normal and beta-thalassemia heterozygotes were: 2.3% 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 chromatographic 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 beta-thalassemia heterozygotes were detected.