title: Diagnosis of diabetes using hemoglobin A1c: should recommendations in adults be extrapolated to adolescents?
abstract: OBJECTIVE
  To compare test performance of hemoglobin A1c (HbA1c) for detecting diabetes mellitus/pre-diabetes for adolescents versus adults in the United States.
  
  
  METHODS
  Individuals were defined as having diabetes mellitus (fasting plasma glucose [FPG] ≥ 126 mg/dL; 2-hour plasma glucose (2-hr PG) ≥ 200 mg/dL) or pre-diabetes (100 ≤ FPG < 126 mg/dL; 140 ≤ 2-hr PG < 200 mg/dL. HbA1c test performance was evaluated with receiver operator characteristic (ROC) analyses.
  
  
  RESULTS
  Few adolescents had undiagnosed diabetes mellitus (n = 4). When assessing FPG to detect diabetes, an HbA1c of 6.5% had sensitivity rates of 75.0% (30.1% to 95.4%) and 53.8% (47.4% to 60.0%) and specificity rates of 99.9% (99.5% to 100.0%) and 99.5% (99.3% to 99.6%) for adolescents and adults, respectively. Additionally, when assessing FPG to detect diabetes mellitus, an HbA1c of 5.7% had sensitivity rates of 5.0% (2.6% to 9.2%) and 23.1% (21.3% to 25.0%) and specificity rates of 98.3% (97.2% to 98.9%) and 91.1% (90.3% to 91.9%) for adolescents and adults, respectively. ROC analyses suggested that HbA1c is a poorer predictor of diabetes mellitus (area under the curve, 0.88 versus 0.93) and pre-diabetes (FPG area under the curve 0.61 versus 0.74) for adolescents compared with adults. Performance was poor regardless of whether FPG or 2-hr PG measurements were used.
  
  
  CONCLUSIONS
  Use of HbA1c for diagnosis of diabetes mellitus and pre-diabetes in adolescents may be premature, until information from more definitive studies is available.
authors.affiliation: Division of Pediatric Endocrinology, University of Michigan, Ann Arbor, MI, USA. joyclee@umich.edu
authors.forename: Joyce M
authors.initials: JM
authors.lastname: Lee
authors.forename: En-Ling
authors.initials: EL
authors.lastname: Wu
authors.forename: Beth
authors.initials: B
authors.lastname: Tarini
authors.forename: William H
authors.initials: WH
authors.lastname: Herman
authors.forename: Esther
authors.initials: E
authors.lastname: Yoon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D002648:Child; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000097:blood* / Q000175:diagnosis*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014481:United States
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human