Distribution of capillary glycated hemoglobin among adolescents of high school age.

Objective: To report the distribution of glycated hemoglobin (hemoglobin A1c or A1C) in whole blood collected from a cohort of high school students with use of a capillary method.

Methods: Students were recruited from the Diabetes Risk Factor Screening Study conducted in Santa Barbara, California, high schools. Height and weight were measured on portable equipment. Blood was collected by finger stick and analyzed immediately for A1C on the DCA 2000+ analyzer. Students also completed a brief survey that included specification of race or ethnicity and family history of diabetes.

Results: Between the years 2001 and 2005, A1C was measured in 2,640 14- to 18-year-old high school students. The mean A1C was 4.91%, SE was 0.01%, and range was from 3.5% to 8.5%, including 2 outliers. Both of these students were found to have previously unrecognized type 2 diabetes mellitus. Male subjects had an A1C that was slightly but significantly higher than that in female subjects (difference = 0.05%; P<.001), subjects with a family history of diabetes in a first-degree relative had higher A1C values than those without such a family history (difference = 0.10%; P = .001), and subjects with a body mass index >or=95% had higher A1C values than did those with a lower body mass index (difference = 0.011%; P<.001). Non-Hispanic white students had A1C concentrations that were significantly lower than those of African American or Latino students. Age had little effect on the A1C.

Conclusion: The A1C distribution in the total study population in this survey was identical to the distribution reported previously with use of the high-performance liquid chromatographic method. This survey establishes standards for capillary A1C in high school students from several racial or ethnic groups.