title: Comparative evaluation of three different methods for HbA1c measurement with High-performance liquid chromatography in diabetic patients.
abstract: BACKGROUND
  The global prevalence of diabetes mellitus is increasing rapidly. Measurement of glycated hemoglobin, predominantly HbA1c, is fundamental to the management of patients with diabetes. HbA1c is used to monitor long-term glycemic control, adjust therapy, assess the quality of diabetes care and predict the risk for the development of complications. While HbA1c is the standard method for long-term glycemic control in diabetic patients, there are different methods for measurement of HbA1c and all laboratories do not use the reference method (high-performance liquid chromatography [HPLC]). The objective of this study is comparison of three different methods with HPLC to find out which method has an acceptable concordance and correlation with the reference method.
  
  
  METHODS
  Fifty-eight diabetic patients were assessed in this study. The blood sample of each patient was checked with Diazyme (enzymatic assay), Nycocard (boronate-affinity binding) and Biosystem (micro column chromatography). The values of HbA1c of each method were compared with the Knauer-HPLC results.
  
  
  RESULTS
  THE MEANS OF THE DIFFERENTIAL VALUES BETWEEN EACH METHOD AND HPLC IN THE ANOVA TEST ARE AS FOLLOWS: M = 1.8, SD = 1.09 for Nycocard-HPLC; M = 1.5, SD = 1.08 for biosystem-HPLC; M = 1.3, SD = 1.2 for Diazyme-HPLC. Pearson's correlation coefficient between HPLC and Nycocard; 0.76, HPLC and Diazyme; 0.75 and between HPLC and Biosystem was 0.68. Linear regression parameters for each method with HPLC were also determined.
  
  
  CONCLUSIONS
  Diazyme had a better performance and showed a greater concordance with HPLC among others, although it was not an ideal alternative for HPLC.
authors.affiliation: Department of Pathology, Isfahan University of Medial Science, Iran.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Karami
authors.affiliation: Department of Pathology, Isfahan University of Medial Science, Iran.
authors.forename: Azar
authors.initials: A
authors.lastname: Baradaran
keywords: Column chromatography; HbA1c; High-performance liquid chromatography; diabetes mellitus; enzymatic assay