The certification of the catalytic activity concentration of creatine kinase in ERM-AD455k/IFCC : certification report

This report describes the production of ERM®-AD455k/IFCC, which is a material certified for the catalytic activity concentration of creatine kinase (CK). This material was produced in collaboration with the International Federation for Clinical Chemistry and Laboratory Medicine (IFCC) following ISO Guide 34:2009 and it is certified in accordance with ISO Guide 35:2006. The starting material was a recombinant form of human CK isoenzyme MM (CK-MM) expressed in E. coli. It was produced, purified, filled and lyophilised by Asahi Kasei Pharma Corporation (Tokyo, Japan). Between unit-homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. The material was characterised by an interlaboratory comparison of laboratories of demonstrated competence and adhering to ISO/IEC 17025:2005. 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 assessment of method performance of the IFCC primary reference measurement procedure for the measurement of the catalytic activity concentration of CK at 37 °C. As with any reference material, it can be used for establishing control charts or validation studies. The CRM is available in glass vials containing lyophilised material from 1 mL of CK solution. The minimum amount of sample to be used is 12 μL after reconstitution of the whole content in one vial. The CRM was accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.