Traceability, reference systems and result comparability.

The standardisation of measurements is of high priority in laboratory medicine, its purpose being to achieve closer comparability of results obtained using routine measurement procedures. At present, there is international cooperation in developing reference measurement systems (reference methods, reference materials, and reference laboratory networks) for analytes of clinical significance. These reference systems will reduce, wherever possible, measurement uncertainty and promote the comparability of results. The implementation of measurement traceability through the reference system provides one of the most important tools that supports the standardisation process in laboratory medicine. It aims to achieve result comparability regardless of the measurement procedure (test kit) and the clinical laboratory where analyses are carried out. The aim of this review is to discuss some concepts related to the achievement of standardisation by the implementation of a metrologically-correct measurement system and to provide some examples that illustrate the complexity of this approach and the impact of these activities on patient care.