EurA _1c : a review of 9 years performance of up to 5120 laboratories in 29 country and 26 manufacturer groups according to current and proposed criteria of the IFCC Model for Quality Targets in relation to the use of HbA _1c for

Abstract Objectives A major objective of the IFCC Committee for Education in the Use of Biomarkers in Diabetes is to monitor the success of global standardization of HbA 1c through benchmark evaluation of the performance by country and manufacturer. Methods From 2016 to 2024 annual trial rounds were organized. Fresh whole blood and lyophilized hemolysate specimens were sent to 29 External Quality Assessment organizers and distributed to up to 5,120 laboratories. Mean results from 2016 to 2024 and from 2024 were evaluated by country and manufacturer, according to current (5 mmol/mol−0.46 %) and proposed (3 mmol/mol−0.28 %) criteria of the IFCC Model for Quality Targets. Results The state of the art in 2024 is an overall bias of 0.6 mmol/mol (0.05 % in NGSP units) with a between laboratory coefficient of variation of 4.0 % (2.7 % in NGSP units). This analytical performance implies that overall 2 % of the laboratories failed to meet the current and 16 % the proposed criterion. Differentiation to country and manufacturer groups showed that 0–10 % of the countries failed to meet the current and 8–35 % the proposed criterion. Of the manufacturers 0–30 % failed to meet the current and 1–58 % the proposed criterion. Results of previous years 2016–2024 were similar. Lyophilized hemolysate specimens were not commutable for some methods. Conclusions The performance of HbA 1c measurement has been stable over the last decade, but substantial differences between country and manufacturer groups were observed. Many met the current criterion, but the picture was mixed when proposing tighter criteria. Whenever possible organizers should use fresh whole blood specimens.