Metrological traceability of calibration in the estimation and use of common medical decision-making criteria.

This manuscript explains the establishment and validation of metrological traceability of calibration for routine measurement procedures using common medical decision-making criteria. Metrological traceability is considered the basis for achieving comparability of measurement results in laboratory medicine. This concept is supported by European legislation, which demands that manufacturers provide assurance and demonstrate metrological traceability of in vitro Diagnostic Medical Devices. The guidance to comply with these legislative requirements is available in different CEN/ISO standards and is used as a basis of this manuscript. The goals and accomplishments in metrological traceability of SI- and non-SI analytes is considered. Specific problems, such as non-availability of primary reference materials and measurement procedures, lack of official endorsement, and non-commutability of certain reference materials are discussed. With respect to non-commutability, the use of split-sample measurements is advocated. Also, the expression of measurement uncertainty associated with the application of the metrological traceability chain is discussed. In addition, the need for post-market vigilance assessment of traceable performance is considered. Finally, laboratory medicine scientific and professional societies, diagnostics manufacturers, and clinicians are urged to share responsibilities for understanding the implications of metrological traceability of routine measurements.