Certification of the amount-of-substance fraction of HbA1c versus the sum of HbA0 and HbA1c in haemoglobin : ERM-AD500/IFCC

This report describes the production of ERM-AD500/IFCC, which is a set of 6 ampoules containing haemoglobin (with different levels of HbA1c) in a buffer solution, certified for the amount-of-substance fraction of HbA1c versus the sum of HbA0 and HbA1c. HbA1c is defined as the stable adduct from glucose and the N-terminal amino group of the β-chain of haemoglobin A0 that is beta-N-(1-deoxyfructose-1-yl) haemoglobin [ ]. The reference material was produced in collaboration with the International Federation for Clinical Chemistry and Laboratory Medicine (IFCC). This material was produced following ISO Guide 34:2009 and is certified in accordance with ISO Guide 35:2006. The ampoules contain buffered solutions of haemoglobin with different amount of substance concentrations of HbA1c and HbA0. The base materials (solutions of purified HbA1c and HbA0) were prepared from whole blood obtained from diabetic volunteers and provided by Roche Diagnostic GmbH, Department for Biochemical Materials, Penzberg, Germany. Mixtures of these base materials were filled into the ampoules, with each ampoule containing approximately 1 mg haemoglobin in 30 μL solution, sealed under an atmosphere of argon. Between-unit homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. The certified value was obtained from the gravimetric preparation of mixtures, taking into account the amount of substance fraction of HbA1c in the two base materials as well as the haemoglobin content determined using the ICSH reference method (Drabkin). The values were confirmed with two datasets obtained using the reference method for HbA1c. Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation. The material is intended for the calibration of the IFCC reference method or for the assessment of method performance. As with any reference material, it can be used for establishing control charts or validation studies. The CRM was accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.