One of the key considerations in improving the harmonisation of clinical laboratory results is that the reference materials (and calibrants) used in laboratory methods should behave in an identical fashion to the analyte being measured in the clinical sample. A commutable reference material achieves this desirable aim. Non-commutable reference materials may be a source of variability between different methods for the same analyte and can contribute to methods giving erroneous results, which may have clinical consequences.
Until recently, commutability was regarded as a ‘black or white’ phenomenon. In other words, a reference material was either fully commutable or non-commutable. Such a classification is now recognised as being unrealistic. To address this matter the IFCC created a Working Group on Commutability, which had input from several international experts.
The IFCC Working Group has examined commutability in a systematic and scientific way and has employed statistics to define the extent to which a reference material is commutable, so helping to determine whether that reference material may be employed with confidence in a clinical laboratory method. The Working Group has published three linked articles in Clinical Chemistry (see below). These articles provide the definitive explanation of commutability and should be of interest to all manufacturers of clinical laboratory diagnostics and to all laboratory medicine specialists.
IFCC Working Group Recommendations for Assessing Commutability. Part 1: General Experimental Design.
Miller WG, Schimmel H, Rej, R, Greenberg N, Ceriotti F, Burns C, Budd JR, Weycamp C, Delatour V, Nilsson G, Mackenzie F, Panteghini, M, Keller T, Camara JE, Zegers I, Vesper HW.
Clin Chem Jan 2018, clinchem.2017.277525;DOI: 10.1373/clinchem.2017.277525
IFCC Working Group Recommendations for Assessing Commutability. Part 2: Using the Difference in Bias between a Reference Material and Clinical Samples.
Nilsson G, Budd JR, Greenberg N, Delatour V, Rej R, Panteghini M, Ceriotti F, Schimmel H, Weycamp C, Keller T, Camara JE, Burns C, Vesper HW, Mackenzie F, Miller WG.
Clin Chem Jan 2018, clinchem.2017.277541;DOI: 10.1373/clinchem.2017.277541
IFCC Working Group Recommendations for Assessing Commutability. Part 3: Using the Calibration Effectiveness of a Reference Material.
Budd JR, Weycamp C, Rej R, Mackenzie F, Ceriotti F, Greenberg N, Camara JE, Schimmel H, Vesper HW, Keller T, Delatour V, Panteghini M, Burns C, Miller WG.
Clin Chem Jan 2018, clinchem.2017.277558;DOI: 10.1373/clinchem.2017.277558