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Hemoglobin A1c assay variations and implications for diabetes screening in obese youth
Author(s) -
Chan Christine L.,
McFann Kim,
Newnes Lindsey,
Nadeau Kristen J.,
Zeitler Philip S.,
Kelsey Megan
Publication year - 2014
Publication title -
pediatric diabetes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.678
H-Index - 75
eISSN - 1399-5448
pISSN - 1399-543X
DOI - 10.1111/pedi.12132
Subject(s) - medicine , concordance , body mass index , prediabetes , diabetes mellitus , hemoglobin , type 2 diabetes , hemoglobin a , endocrinology
Background Standardization of the hemoglobin A1c (A1c) assay has led to its increasing utilization as a screening tool for the diagnosis of prediabetes and type 2 diabetes in youth. However, significant A1c assay variability remains and has implications for clinical management. Objective To describe our center's experiences with A1c results in youth and to evaluate inter‐method differences and their clinical implications. Subjects Seventy‐five youth (aged 10–18 yr old), body mass index ( BMI ) ≥85th‰ participated. Methods Seventy‐two participants had two A1c values performed on the same sample, one via immunoassay ( DCA Vantage Analyzer, A1c 1 ) and the other via high performance liquid chromatography (Bio‐Rad Variant II , A1c 2 ). Nineteen had A1c run on two immunoassay devices (A1c 1 and Dimensions Vista, A1c 3 ). Results Mean age of participants was 13.9 years, BMI % 97.89%, 33% male, 16% white, 21% black, and 61% Hispanic (H). Mean A1c 1 was 5.68% ± 0.38 vs. a mean A1c 2 of 5.73% ± 0.39, p = 0.049. Concordance in diabetes status between methods was achieved in 79% of subjects. Nineteen subjects with A1c 3 results had testing performed an average of 22 ± 9 days prior to A1c 1 . Mean A1c 3 was 6.24% ± 0.4, compared to a mean A1c 1 of 5.74% ± 0.31, (p < 0.0001). A1c 1 was on average systematically −0.5 ± 0.28 lower compared to A1c 3 . There was poor agreement in diabetes classification between A1c 1 and A1c 3 , with a concordance in classification between methods of only 36.8%. Conclusions Clinically significant inter‐method A1c variability exists that impacts patient classification and treatment recommendations. In the screening of obese youth for diabetes, A1c results should be interpreted with caution.