title: Direct enzymatic assay for %HbA1c in human whole blood samples.
abstract: OBJECTIVE
  Development and validation of a direct enzymatic HbA1c assay that utilizes a single channel on chemistry auto-analyzers without the need to run separate glycated hemoglobin and total hemoglobin assays.
  
  
  METHODS
  An enzyme based single channel assay was developed to measure %HbA1c in human whole blood samples. The performance characteristics of the Diazyme Direct Enzymatic HbA1c Assay were evaluated on the Hitachi 917 auto-analyzer using whole blood samples, appropriate controls and a reference lot of manufactured reagents. Accuracy studies were completed by comparing the Direct Enzymatic Assay to existing HPLC and immunoassay methods. Interference testing was performed to determine the effect of total hemoglobin, glycated serum proteins, chemical substances and hemoglobin variants in patient samples.
  
  
  RESULTS
  The Direct Enzymatic HbA1c Assay showed within run precision and total precision results of < or = 2% CV for both normal and abnormal level samples. Method comparison studies showed that there was a good correlation between the Direct Enzymatic HbA1c and the HPLC (R(2)=0.98) or the immunoassay (R(2)=0.97) methods. The assay measured within the range of 4-16% HbA1c and showed excellent performance with variant hemoglobin in samples.
  
  
  CONCLUSIONS
  Diazyme Direct Enzymatic HbA1c Assay is accurate and precise when compared to currently marketed medical devices. The assay is designed to report %HbA1c values directly without need for a separate measurement of total hemoglobin and is not adversely affected by interferences from common hemoglobin variants in samples. It is a cost effective, user-friendly method and is adaptable to most general chemistry analyzers.
authors.affiliation: Diazyme Laboratories, 12889 Gregg Court, Poway, CA 92064, USA.
authors.forename: Limin
authors.initials: L
authors.lastname: Liu
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hood
authors.forename: Yuping
authors.initials: Y
authors.lastname: Wang
authors.forename: Robert
authors.initials: R
authors.lastname: Bezverkov
authors.forename: Chao
authors.initials: C
authors.lastname: Dou
authors.forename: Abhijit
authors.initials: A
authors.lastname: Datta
authors.forename: Chong
authors.initials: C
authors.lastname: Yuan
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods / Q000592:standards; D006442:Glycated Hemoglobin / Q000032:analysis* / Q000378:metabolism* / Q000592:standards; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods* / Q000592:standards; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D006442:Glycated Hemoglobin