Convenient screening for hemoglobin variants by using the Diamat HPLC system.

Hemolysates from 102 different patients previously assessed for the presence of hemoglobin variants by cellulose acetate electrophoresis were reanalyzed with the Diamat, a microprocessor-controlled step-gradient HPLC technique designed to determine glycohemoglobin (Hgb A1c). This pool contained 81 abnormal specimens, each with one of seven different variant abnormalities. In all cases the HPLC technique correctly detected the presence or absence of a variant. The common S trait gave a large peak immediately after Hgb A, and the SS and SC variants gave clearly abnormal patterns, caused in part by the absence of Hgb A. The pattern from EE variants was distinguished by the appearance of the glycated fraction Hgb E1c, which is eluted at 4.7 instead of 4.2 min, whereas the AE pattern had two glycated peaks. Hemoglobins F, "fast", S, and C were discerned by the presence of a major peak at 3, 5.2, 6.5, and 7.5 min, respectively. The findings suggest that the Diamat is a convenient tool to detect and help diagnose variants in a screening pool.