Characterization of the New Serum Protein Reference Material ERM-DA470k/IFCC: Value Assignment by Immunoassay


Characterization of the New Serum Protein Reference Material ERM-DA470k/IFCC: Value Assignment by Immunoassay

I Zegers, T Keller, W Schreiber, J Sheldon, R Albertini, S Blirup Jensen, M Johnson, S Trapmann, H Emons, G Merlini and H. Schimmel

Clinical Chemistry, 2010, 56(12), 1880-1888. DOI: 10.1373/clinchem.2010.148809

Abstract

BACKGROUND:

The availability of a suitable matrix reference material is essential for standardization of the immunoassays used to measure serum proteins. The earlier serum protein reference material ERM-DA470 (previously called CRM470), certified in 1993, has led to a high degree of harmonization of the measurement results. A new serum protein material has now been prepared and its suitability in term of homogeneity and stability has been verified; after characterization, the material has been certified as ERM-DA470k/IFCC.

METHODS:

We characterized the candidate reference material for 14 proteins by applying a protocol that is considered to be a reference measurement procedure, by use of optimized immunoassays. ERM-DA470 was used as a calibrant.

 RESULTS:

For 12 proteins [2 macroglobulin (A2M), 1 acid glycoprotein (orosomucoid, AAG), 1 antitrypsin (1-protease inhibitor, AAT), albumin (ALB), complement 3c (C3c), complement 4 (C4), haptoglobin (HPT), IgA, IgG, IgM, transferrin (TRF), and transthyretin (TTR)], the results allowed assignment of certified values in ERM-DA470k/IFCC. For CRP, we observed a bias between the lyophilized and liquid frozen materials, and for CER, the distribution of values was too broad. Therefore, these 2 proteins were not certified in the ERM-DA470k/IFCC. Different value transfer procedures were tested (open and closed procedures) and found to provide equivalent results.

 CONCLUSIONS:

A new serum protein reference material has been produced, and values have been successfully assigned for 12 proteins.

ASCI-ID: 1446-340