Clinically relevant lot-to-lot reagent difference in a commercial immunoturbidimetric assay for glycated hemoglobin A1c

The subsequent A1C3 reagent lot yields significantly higher measurement results than the initial by approximately 0.5% HbA1c (5.5 mmol/mol). This difference is considered as clinically relevant. A combined effort of manufacturers and notified bodies is necessary to minimize lot-to-lot variation.