[Reference material (CRM 470) for serum proteins: preparation, characteristics and conditions of use]

Several national and international quality assurance schemes clearly demonstrated the discrepancies between the results given by different analytical systems designed for the immunochemical measurement of proteins. Thus, the need for the preparation of a new international secondary reference material appeared urgent to the International Federation for Clinical Chemistry (IFCC). In this paper, the authors describe the different steps of the preparation of the new standard CRM 470. This work financed by the Bureau Communautaire de Référence (BCR) has been done in collaboration with the College of American Pathologists (CAP). The physicochemical properties of the proteins present in the CRM 470 and the various controls undertaken on the preparation are described. The CRM 470 material (40,000 lyophylised 1 ml vials) is now certified for the 14 plasma proteins of major interest in clinical chemistry. The worldwide introduction of this material will considerably improve the accuracy of immunochemical proteins' determination and will allow the determination of the reference values as a function of age and sex.