Certification of the amount-of-substance fraction of haemoglobin A2 versus total haemoglobin in blood haemolysate : ERM®-DA485/IFCC and ERM®-DA486/IFCC

ERM®-DA485/IFCC and ERM®-DA486/IFCC are blood haemolysate materials certified for the amount-of-substance fraction of haemoglobin A2 versus total haemoglobin, produced within the scope of ISO 17034 accreditation [1]. The CRMs are available in glass vials containing at least 2 mL of blood haemolysate, lyophilised into a dry powder. The vials were sealed under an atmosphere of nitrogen. Between-unit homogeneity was quantified and stability during transport and storage was assessed in accordance with ISO 33405:2024 [2]. The minimum volume of reconstituted material to be used for one measurement is 5 μL. This minimum sampling volume gave acceptable repeatability using this sample volume, the within-unit inhomogeneity did not contribute to variation of measurement. The materials were characterised by a reference method [3] through an interlaboratory comparison of laboratories of demonstrated competence and adhering to ISO/IEC 17025:2017 [4]. All data sets obtained were found technically valid. Uncertainties of the certified values were calculated in accordance with ISO 17034:2016 [1] and include uncertainties related to possible inhomogeneity, instability and characterisation. The materials are intended for the calibration of various analytical methods used for the quantification of the amount-of-substance fraction of haemoglobin A2 versus total haemoglobin in human blood. Before release of the CRMs, the certification project was subjected to peer-review involving both internal and external experts.