A global multicenter study on reference values: 1. Assessment of methods for derivation and comparison of reference intervals

•A global multicenter study on reference values (RVs) was conducted targeting 50 analytes using a common protocol.•A panel of sera were measured in common for alignment of RVs across 12 countries.•Need for secondary exclusion of RVs was obvious in analytes which reflect nutritional abnormalities.•Validity of parametric method was confirmed by almost invariable success in Gaussian transformation•Nearly half of the analytes showed variable degrees of between-country differences.