Innovations in HbA analysis: finding the balance between speed and accuracy. An investigation of a potential new Secondary Reference Measurement Procedure for the IFCC.

Objectives: The escalating prevalence of diabetes worldwide has resulted in a dramatic increase in the number of people who need testing, which in turn necessitates faster HbA measurement. The Tosoh GR01 addresses the need for fast turnaround times of whilst offering pragmatic steps to maintain result accuracy in a single instrument by offering two distinct operating modes: Short Mode (SM) and Long Mode (LM). The aim of this study was to evaluate all relevant aspects of the performance of the Tosoh GR01 with a view to accepting the instrument as a future Secondary Reference Measurement Procedure (SRMP) for the IFCC.

Methods: Certified Clinical & Laboratory Standards Institute (CLSI) Evaluation Protocols (EP) were used to evaluate precision (EP-5), accuracy (EP-9), linearity (EP-6), carry-over (EP-10) and the effect of hemoglobin variants and other potential interferences.

Results: Both modes demonstrated CVs <0.6 % in SI units and <0.4 % in NGSP units at 46 mmol/mol (6.4 %) and 75 mmol/mol (9.0 %) and passed both National Glycohemoglobin Standardization Program (NGSP) and International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) certification procedures when compared with 7 IFCC Certified Secondary Reference Measurement Procedures (SRMP). Sigma for both modes was >6 when using the results of EP-5 and EP-9 at an HbA concentration of 50 mmol/mol (6.7 %). Neither mode showed any interference with common Hb-variants except for HbAE when HbA was >65 mmol/mol. In the SM HbAS, HbAD and HbAC were recognized but no result was reported.

Conclusions: There is a good balance between speed and accuracy for determining HbA with the Tosoh GR01 in both analytical modes and the device is suitable for use as an IFCC SRMP.