title: Hemoglobin A1c: assessment of three POC analyzers relative to a central laboratory method.
abstract: BACKGROUND
  Glycosylated hemoglobin evaluation is very important for assessing the control of diabetes. Since the use of point-of-care (POC) devices for monitoring HbA1c is increasing, it is important to determine how these devices compare in relation to instrumentation used in the central laboratory (CL).
  
  
  METHODS
  Eighty-eight randomly selected samples previously analyzed using the Bio-Rad Variant™ II Hemoglobin Testing System were run on three POC Analyzers (Siemens DCA Vantage™ Analyzer, Axis-Shield Afinion™ AS100 Analyzer, and Bio-Rad In2it™ Analyzer).
  
  
  RESULTS
  All POC instruments showed good correlation to the CL method (R(2)>0.95 for all methods). HbA1c levels obtained using Variant II (mean=7.9; 95% CI=7.5-8.3%) and In2it (mean=7.9; 95% C.I.=7.5-8.2%) instruments were found to have no statistical mean difference (p=0.21), while the values obtained using DCA Vantage (mean=7.2% C.I.=6.9-7.5%) and Afinion (mean=7.3% C.I.=7.0-7.6%) instruments were different (p<0.001) from those of the CL method. The Afinion and DCA Vantage instruments increasingly underestimated the HbA1c compared to the CL as the HbA1c values increased. These differences were even more striking when the estimated average glucose is calculated.
  
  
  CONCLUSIONS
  Despite significant variation of results among the POC instruments evaluated relative to the CL method and pending resolution of HbA1c standardization issues, we conclude that all of the POC instruments can be used for HbA1c determination if clinicians are given instrument specific reference ranges.
authors.affiliation: Department of Pathology, University of Texas Medical Branch, United States. jrpeters@utmb.edu
authors.forename: John R
authors.initials: JR
authors.lastname: Petersen
authors.forename: Felix O
authors.initials: FO
authors.lastname: Omoruyi
authors.forename: Amin A
authors.initials: AA
authors.lastname: Mohammad
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Shea
authors.forename: Anthony O
authors.initials: AO
authors.lastname: Okorodudu
authors.forename: Hyunsu
authors.initials: H
authors.lastname: Ju
mesh_terms: D000704:Analysis of Variance; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007753:Laboratories / Q000592:standards*; D019095:Point-of-Care Systems; D012015:Reference Standards; D013997:Time Factors
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human