Recommendations for assessing commutability part 2: based on the difference in bias between a reference material and clinical samples

Published

January 18, 2018

Author(s)

Johanna Camara, Goran Nilsson, Jeffrey R. Budd, Neil Greenberg, Vincent Delatour, Gerhard Schumann, Robert Rej, Mauro Panteghini, Ferruccio Ceriotti, Schimmel Heinz, Weykamp Cas, Thomas Keller, Chris Burns, Finlay MacKenzie, W. Greg Miller

Abstract

A process is described to assess the commutability of a reference material intended for use as a calibrator, trueness control or external quality assessment sample based on the difference in bias between a reference material and clinical samples measured using two different measuring systems. This difference in bias is compared to a criterion based on a medically relevant difference between a reference material and clinical sample results to make a conclusion regarding commutability. When more than two measuring systems are included, the commutability is assessed pair-wise for all combinations of two measuring systems. This approach allows the same criterion to be used for all combinations of measuring systems included in the assessment. The assessment is based on an error model that allows estimation of various random and systematic sources of error including that from sample specific effects of interfering substances. An advantage of this approach is that the difference in bias between a reference material and the average bias of clinical samples at the concentration (i.e. amount of substance present or quantity value) of the reference material is determined and its uncertainty estimated. A reference material is considered fit for purpose for those measuring systems where commutability is demonstrated.

Citation

Clinical Chemistry

Pub Type

Journals

Download Paper

https://doi.org/10.1373/clinchem.2017.277541

Keywords

commutability, difference in bias

Citation

Camara, J. , Nilsson, G. , Budd, J. , Greenberg, N. , Delatour, V. , Schumann, G. , Rej, R. , Panteghini, M. , Ceriotti, F. , Heinz, S. , Cas, W. , Keller, T. , Burns, C. , MacKenzie, F. and , W. (2018), Recommendations for assessing commutability part 2: based on the difference in bias between a reference material and clinical samples, Clinical Chemistry, [online], https://doi.org/10.1373/clinchem.2017.277541 (Accessed October 8, 2025)