Analytical verification and quality assessment of the Tosoh HLC-723GX HbA1c analyzer

OBJECTIVES Ion-exchange high-performance liquid chromatography (IE-HPLC) has long been used as a reproducible and versatile analytical tool for HbA1c measurement. In this study, we performed analytical verification and quality assessment of the recently introduced small IE-HPLC Tosoh HLC-723GX HbA1c analyzer, and a comparison of results to immunoassay (IA) and capillary electrophoresis (CE). DESIGN AND METHODS The total imprecision of Tosoh HLC-723GX was verified according to CLSI EP15-A2 protocol using commercial control materials (C-QC) and pooled human whole blood samples (HWB). The Sigma metric was used for the evaluation of quality targets. HbA1c results were compared to automated CE (MiniCap Flex Piercing, Sebia, France) and IA (Tina-quant HbA1c Gen 2, Cobas Integra 400+, Roche Diagnostics, USA) procedures. RESULTS The total imprecision of Tosoh HLC-723GX-HbA1c for IFCC(mmol/mol) and NGSP(%) units was: 1.91/1.25% (HbA1c=31 mmol/mol/5.0%) and 0.51/0.63% (HbA1c=84 mmol/mol/9.8%) for C-QC, and 0.39/0.2% (HbA1c=47 mmol/mol/6.5%) and 0.77/0.46% (HbA1c=94 mmol/mol/10.8%) in HWB samples, respectively. Bland-Altman analysis did not reveal any deviation of the results between Tosoh HLC-723GX and CE: mean difference 0.0% (95%CI: -0.02927 to 0.02653%), while the mean HbA1c difference against IA was -0.07% (95%CI: -0.1039 to -0.02765). At the selected HbA1c clinical decision level (48 mmol/mol/6,5%), six sigma analysis gave σ value of 3.91, within a desirable classification of performance. CONCLUSION The analytical performance of the Tosoh HLC-723GX complies with the rigorous quality criteria for clinical use of HbA1c, with the results comparable to the CE procedure. Tosoh HLC-723GX provides a plausible analytical choice for reliable HbA1c measurement in low-volume laboratories.