Opinion Paper: Deriving Harmonised Reference Intervals – Global Activities

Harmonisation of reference intervals (RIs) refers to use of the same or common RI across different platforms and /or assays for a specified analyte. It occurs optimally for those analytes where there is sound calibration and traceability in place and evidence from a between-method comparison shows that bias would not prevent the use of a common RI. The selection of the RI will depend on various sources of information including local formal RI studies, published studies from the literature, laboratory surveys, manufacturer’s product information, relevant guidelines, and mining of databases. Pre-analytical and partitioning issues, significant figures and flagging rates, are assessed for each analyte. Several countries and regions including the Nordic countries, United Kingdom, Japan, Turkey, and Australasia are using common RIs that have been determined either by direct studies or by a consensus process. In Canada, the Canadian Society of Clinical Chemists Taskforce is assessing the feasibility of establishing common reference values using the CALIPER (Canadian Laboratory Initiative on Pediatric Reference Intervals) and CHMS (The Canadian Health Measures Survey) databases as the basis. Development of platform-specific common reference values for each of the major analytical systems may be a more practical approach especially for the majority of analytes that are not standardised against a primary reference method and are not traceable to a primary or secondary reference material. We encourage laboratories to consider adopting reference intervals consistent with those used by other laboratories in your region where it is possible and appropriate for your local population. Local validation of the adopted reference interval is also recommended as per CLSI guidelines.