Comparison of Turbidimetric Inhibition Immunoassay, High-Performance Liquid Chromatography, and Capillary Electrophoresis Methods for Glycated Hemoglobin Determination.

OBJECTIVE: The purpose of this study was to compare the performances of and evaluate the agreement among glycated hemoglobin values analyzed by using National Glycohemoglobin Standardization Program-certified and International Federation of Clinical Chemistry-standardized analyzers. THIS CROSS-SECTIONAL STUDY WAS CONDUCTED AT THE: Armed Forces Institute of Pathology, Department of Chemical Pathology from March 2019 to May 2019. METHODS: Glycated hemoglobin (HbA1c) was measured in the blood specimens from 100 patients on an ADVIA 1800 by a turbidimetric inhibitory immunoassay (TINIA), Sebia instrument by electrophoresis, and Bio-Rad Variant II Turbo system by high-performance liquid chromatography (HPLC). Quantitative variables were calculated as the mean +/- standard deviation (SD). Precision and method comparisons were carried out according to Clinical and Laboratory Standards Institute recommendations. The results obtained from each analyzer were compared by correlation analysis. Method comparison was done by linear regression and Bland-Altman plots using the SPSS software version 24. RESULTS: The mean +/- SD HbA1c values from TINIA, electrophoresis, and HPLC were 7.188% +/- 1.89%, 7.164% +/- 1.866%, and 7.160% +/- 1.85%, respectively. The between-run coefficients of variation for TINIA, electrophoresis, and HPLC were 0.64%, 0.61%, and 0.60%, respectively. All 3 showed good correlation (TINIA, R2 = .994, P = .00; electrophoresis, R2 = .992, P = 0.00; and HPLC, R2 = .994, P = 0.00). CONCLUSION: The good clinical agreements of HbA1c and strong correlations between analyzers indicate that these analyzers can be used interchangeably.