Four Assay Methodsfor Glycated HemoglobinCompared as ScreeningTests for Diabetes Mellitus:The lslingtonDiabetes Survey

We assessedthe utility of four methods of glycated hemoglo-bin assay (agar gel electrophoresis with Schiff base, agar gel electrophoresis with prior removal of Schiff base, boronate affinity chromatography, and isoelectric focusing) as screen-ing tests for diabetes mellitus, studying 223 subjects under-going an oral glucose-tolerance test after fasting and2 h after ingestion of 75 g of glucose. Assessment of glucose toler-ance status according to the 1980 World Health Organization diagnostic criteria indicated that 13 subjects (5.8%) had diabetes, 48 (21.5%) had impaired glucose tolerance, and nine (4.0%) could not be classified (six of these because of missing values). Use of receiver-operating characteristic curves to compare the assays as screening tests showed the affinity chromatography assay to be superior. Assays for glycated hemoglobin after fasting had better precision than post-glucose-load assays as screening tests, and test char-acteristics of glycated hemoglobin assays on fasting subjects were similar to those of the blood-glucose estimation after fasting. We conclude that measurement of glycated hemo-globin may be a useful screening test for diabetes, and that such measurement of stable glycated hemoglobin is as accurate as measurement of lasting blood-glucose in screen-ing for diabetes. For this use, we found methods that measure stable glycated hemoglobin superior to that mea-suring both stable and labile Schiff-base fractions. AddItIonal Keyphraees: chromatography, affinity. electrophore