title: Evaluation of hemoglobin A1c measurement by Capillarys 2 electrophoresis for detection of abnormal glucose tolerance in African immigrants to the United States.
abstract: BACKGROUND
  Hemoglobin A1c (HbA1c) is used to monitor long-term glycemic control in individuals with diabetes, guide therapy, predict the risk of microvascular complications, and more recently to diagnose diabetes. An automated liquid-flow capillary electrophoresis method was recently developed to measure HbA1c using the Capillarys 2 Flex Piercing instrument.
  
  
  METHODS
  Analytical evaluation was performed at 2 clinical centers. A clinical analysis was conducted in 109 African-born individuals, 24% of whom have variant hemoglobin (HbAS or HbAC). Abnormal glucose tolerance (which includes both diabetes and prediabetes) was defined as 2h glucose of ≥ 140 mg/dl (7.8 mmol/l) during an oral glucose tolerance test.
  
  
  RESULTS
  Interlaboratory CVs were ≤ 2.1%. The method showed satisfactory correlation with 2 other analyzers that measure HbA1c by high-performance liquid chromatography. Neither labile HbA1c, carbamylated hemoglobin, uremia, bilirubin nor common hemoglobin variants (HbC/HbS/HbE) interfered. Forty-five individuals (41%) had abnormal glucose tolerance. The sensitivity of HbA1c for diagnosing abnormal glucose tolerance was 38%, 36% and 42% for total, normal and variant hemoglobin groups, respectively.
  
  
  CONCLUSIONS
  The analytical performance of HbA1c on the Capillarys 2 is suitable for clinical application. Variant hemoglobin in Africans did not interfere with the detection of abnormal glucose tolerance by HbA1c measured on the Capillarys 2.
authors: Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States.
authors: Zhen
authors: Z
authors: Zhao
authors: Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States.
authors: Jeffrey
authors: J
authors: Basilio
authors: Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, United States.
authors: Steven
authors: S
authors: Hanson
authors: Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, United States.
authors: Randie R
authors: RR
authors: Little
authors: Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States. Electronic address: annes@intra.niddk.nih.gov.
authors: Anne E
authors: AE
authors: Sumner
authors: Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States. Electronic address: david.sacks2@nih.gov.
authors: David B
authors: DB
authors: Sacks
mesh_terms: D000349:Africa / Q000208:ethnology; D000755:Anemia, Sickle Cell / Q000097:blood / Q000175:diagnosis; D001786:Blood Glucose / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000592:standards; D054242:Emigrants and Immigrants; D005951:Glucose Tolerance Test / Q000592:standards; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D014481:United States / Q000208:ethnology
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: Abnormal glucose tolerance; Africans; Capillarys 2; Diabetes; Hemoglobin A1c; Sickle cell