Topic outline

  • The role of EQA in the verification of in vitro medical diagnostics

    Federica BragaSpeaker: Federica Braga (IT)
    Moderator: Anne Stavelin (NO)

    Date: 17th April 2018 18:00 CET

    Abstract

    Once an in-vitro diagnostic measuring system has been marketed and introduced into daily practice, the possible sources of degradation of its performance are numerous. It is therefore essential to put in place a continuous surveillance of the quality of performance of the commercial system and of the laboratory that perform measurements in clinical setting. This surveillance relies substantially on quality control programs, which, however, should be redesigned to meet metrological criteria. Particularly, the participation to EQA schemes that meet specific metrological criteria is mandatory for the evaluation of performance of participating laboratories in terms of standardization and clinical suitability of their measurements. The requirements for this type of EQA are as follows: in addition to the use of commutable control materials to allow transferability of participating laboratory performance to patient samples, it is necessary to assign values (and uncertainty) to them with reference measurement procedures (RMP) performed by an accredited laboratory and to define and apply clinically allowable performance specifications to verify the suitability of laboratory measurements in a clinical setting. Unfortunately, there are few permanent EQA programs covering these requirements because some practical constraints including technical (lack of certified materials, difficulties to prepare commutable samples, complicated logistics of distribution of frozen samples), psychological (lack of awareness of which quality factors make an EQA important) and economic (higher costs) aspects, which limit their introduction. It should be however emphasized how the lack of properly structured EQA schemes prevents the objective evaluation of the reliability of measuring systems and of the quality of analytical measurements provided by clinical laboratories. Only true value assignment by RMP to EQA commutable materials allows objective evaluation of the performance of laboratory measurements through a trueness-based (instead of inferior consensus-based) grading of the competency of participating clinical laboratories. Note that for quantities where no high-order RMP is available, system-dependent target values should be used to evaluate the performance of participating laboratories, but also in this case the values assigned to the EQA materials should preferentially be determined by reference institutions (possibly including the manufacturer releasing that specific analytical system), working under strictly controlled conditions in order to maintain measurement uncertainty as low as possible, and not as a group mean. The fulfillment of requirements for the applicability of EQA results in competence classification of participating laboratories in terms of traceability of their measurements involves both technical and economic efforts by EQA organizers. It is, however, clear that these aspects should be immediately solved since EQA that meet metrological criteria have unique benefits that add substantial value to the practice of laboratory medicine. The main purpose of an optimal EQA program must be to evaluate the analytical quality of laboratory measurements, including the traceability of the calibration and of patient results and the equivalence among laboratories for the obtained results. EQA schemes are therefore in a unique position to add substantial value to the practice of Laboratory Medicine, by identifying analytes that need improved harmonization and by stimulating and sustaining standardization initiatives that are needed to support clinical practice guidelines. This will definitively help those manufacturers that produce superior products to demonstrate the superiority of those products and oblige users (and consequently industry) to abandon assays with demonstrated insufficient quality.

    About the speaker

    Federica Braga received her post-graduation cum laude at the School of Specialization in Clinical Biochemistry of the University of Milan. She is currently working as a Researcher at Clinical Pathology Unit of the “Luigi Sacco” University Hospital in Milan, Italy. She is member of the Biological Variation Working Group of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) and member of the EFLM Task and Finish Group on Biological Variation Database, with the aim to generate a database with essential information about the biological variation and derived performance specifications for different measurands. She has authored and co-authored 34 papers published on peer-reviewed journals and 16 abstracts.

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