Teoria e pratica degli intervalli di riferimento riferibili

Theory and practice of traceable reference intervals.An issue associated with standardization efforts is the need to develop useful reference intervals. Lack of proper reference intervals may indeed hamper the implementation of standardization in Laboratory Medicine as standardization can modify analyte results and, without adequate reference intervals, this can impair the result interpretation. Once defined, reference intervals obtained with analytical procedures that produce results traceable to the corresponding reference system can be transferred among laboratories, providing that they use commercial assays that produce results traceable to the same reference system and populations have the same characteristics. Multicenter studies are needed for a robust definition of traceable reference intervals, using experimental protocols that include well defined prerequisites. Particularly, employed methods must produce results that are traceable to the reference system for that specific analyte. Thus, the trueness of laboratories producing reference values should be verified and, if necessary, experimental results corrected in accordance with correlation results with the selected reference. If requirements in the adoption of traceable reference intervals are fulfilled, the possibility of providing reference intervals that are applicable to any laboratory, able to produce results traceable to the reference system, is realistic. The definition of traceable reference intervals should hopefully cause the disappearance of different reference intervals employed for the same analyte, providing more effective information to clinicians.