RESUMO
The primary reference measurement procedures (PRMPs) for the international standardization of catalytic concentration measurements of alpha-amylase, alanine aminotransferase, aspartate aminotransferase (AST), creatine kinase (CK), gamma-glutamyltransferase and lactate dehydrogenase have been performed in reference laboratories for several years. The IFCC Committee on Reference Systems for Enzymes and two reference laboratories, with official accreditation for the PRMPs, have collected useful information on some of the steps of the reference procedures that require special attention. This document comprises errata corrige for minor mistakes in published PRMPs for AST and CK. Several notes on the PRMPs are emphasized. This includes details that are very important for improved standardization, and general suggestions for reducing measurement uncertainty.