GLYCOHEMOGLOBIN ASSAYS EVALUATED IN A LARGE-SCALE QUALITY-CONTROL SURVEY

We report the results of a national quality-control survey on glycohem oglobin (GHb), monitored in France by the Societe Francaise de Biologi e Clinique on behalf of the authority of the ''Agence du Medicament.'' A sample of lyophilized hemolysate was sent to 3109 laboratories. Res ults were obtained from 2770 laboratories. HbA(1c), HbA(1), and total GHb were measured by 50%, 24%, and 26% of the participants, respective ly. Of these measurements, 79% of the HbA(1c) results and 76% of the t otal GHb results, but only 48% of the HbA(1) results, were within the +/- 20% limits of the indicated target values, Mean values for the hem olysate ranged from 8% to 11% for HbA(1c), from 7% to 12% for HbA(1), and from 11% to 13% for total GHb. The interlaboratory CVs ranged from 3% to 20%, according to method used, So, methods used for GHb assay, which are based on various principles, exhibit very different analytic al performances, Nonetheless, this large-scale study indicates that so me techniques can support transferability of results from laboratory t o laboratory.