Specification of analytical limits of EQA programs using biological variations. A tool enabling the link between analytical quality and clinical effectiveness

Overview

EQA programs are not only a required condition for operation of clinical laboratories, but also have great potential for assessing the analytical and clinical effectiveness of laboratory tests. During their further development, great emphasis should be placed on the processes of harmonization of results and thus on achieving their maximum clinical effectiveness. A key tool in this process is the derivation of control limit values using biological variations (APS BV). This communication summarizes the data obtained from the intensive efforts of the EFLM Biological Variation Working Group EuBIVAS, describes their current status and discusses their impact on improving the clinical validity of laboratory tests. The possible consequences of this approach and the influence of various criteria on diagnostic decision-making and monitoring of the patient's condition are considered. The interpretation of EQA results in terms of greater emphasis on either accuracy or bias of measurements may be affected. A change of approach to the evaluation limits of the EQA programs is absolutely necessary in the long run, but its reasonable application seems just as necessary. An approach based on biological variations will lead to the much-needed harmonization of the laboratory quality assessment process itself, to the justification of the results of the application of this approach and also to the physical and mental emancipation of laboratory staff from commercial interests. In practice, however, a careful balance needs to be struck when applying this more modern approach with regard to the current state of evaluation of EQA programs based on conventional state-of-the-art approaches. However, since the development of laboratory tests leading to harmonization is necessary and unavoidable and because the number of analytes with known values of biological variation is constantly growing (34 of them are presented in this work), it would be appropriate to use new criteria based on APS BV in addition to the traditional EQA criteria, preferably in the form of educational, clinically optimal tolerance limits.

Keywords:

biological variation – EuBIVAS – EQA schemes – analytical performance specification (APS) – optimal clinical values