GB/T 21415－2025 is identical to ISO 17511: 2020 and replaces GB/T 21415－2008. It extends metrological traceability requirements from calibrators and control materials to values assigned to human samples, and introduces enhanced elements such as maximum allowable expanded measurement uncertainty, validation of metrological traceability, commutability assessment, and international harmonization protocols. This article systematically reviews the scope, general requirements, and the six calibration hierarchy structures of the standard. It focuses on key implementation aspects including the definition of the measurand, selection of reference systems, uncertainty budget allocation, and commutability. In addition, it clarifies the responsibilities and requirements for in vitro diagnostic medical device manufacturers, reference material producers, reference measurement laboratories, and medical laboratories, aiming to help relevant institutions establish applicable and verifiable value-transfer chains and to promote accuracy, comparability and mutual recognition of test results.