Traceability as a unique tool to improve standardization in laboratory medicine.

The standardization of measurements is of high priority in Laboratory Medicine, its purpose being to achieve closer comparability of results obtained using routine analytical systems. In order to achieve standardization, an approach is required that provides reliable transfer of the measurement values from the highest hierarchical level to methods which are routinely used in the clinical laboratories. Such a structure is presented by the reference measurement system (RS), based on the concepts of metrological traceability. Key elements of a comprehensive RS are the reference measurement procedure and reference materials. Other essential elements include the definition of the measurand in regards to the intended clinical use and the reference laboratories that may collaborate in a network. At present, there is international cooperation in developing RS for analytes of clinical significance. Thanks to the work of the Joint Committee on Traceability in Laboratory Medicine (JCTLM), a list of higher order reference materials and reference methods is now publicly available. JCTLM has also published the list of reference laboratories that are able to deliver a reference measurement service. As soon as a new RS is implemented, clinical validation of the correctly calibrated routine methods (the IVD products sold onto the market) should take place. Other important issues concerning the implementation of a metrologically-correct approach for result standardization are: 1) the clear definition of the clinically allowable error of measurements and 2) the post-market surveillance of the performance of IVD products. These are tasks of our profession through the organization of appropriate External Quality Assessment programs.