Pilot External Quality Assessment Survey for Post-Market Vigilance of In Vitro Diagnostic Medical Devices and Investigation of Trueness of Participants' Results

Abstract

The Czech External Quality Assessment Scheme organized a survey using 14 fresh-frozen sera targeted for cholesterol and glucose by reference measurement procedures. The objective was to investigate whether it could fulfil a post-market vigilance function for in vitro diagnostic medical devices and assess trueness of participants' results. It revealed a mean bias of +5.1% for cholesterol and +3.7% for glucose (n approximately 150). However, the bias source (manufacturer or laboratory) could not be identified unequivocally because of the lack of homogeneous groups. This was due to the fact that laboratories mainly used reagents from manufacturers that do not market instruments or combined calibrators and reagents from different sources. Consequently, these habits did not allow the survey to fulfil the vigilance function. On the other hand, we were able to show the individual participants results for patient samples deviating from the true value (deviations >10% in approximately 20% of the laboratories). However, again, the survey failed in problem-solving via peer-group evaluation, even for participants that applied homogeneous tests. If other European schemes confirm this outcome, cooperation and/or participation of manufacturers may be the solution. The survey pointed out to the other participants, interchanging instrument, reagent and calibrator, that they are themselves responsible for the problems shown and hence also for problem-solving.

Impact of quality control matrix effect: application to the calculation of uncertainty of measurement in one-stage clotting factor VIII assay

“…At an international level, its interest is highly controversial [5][6][7]. The rationale of the present study was that we suspected that uncertainty of measurement was being overestimated when calculated from the EQC consensus data provided by the ECAT Foundation.…”

“…There have been few reports of GUM as applied in medical analysis laboratories [3]. In the opinion of many authors, indeed, the concept of uncertainty of measurement debases the quality assurance paradigms according to which biologists, like any other manufacturer, should qualify biological results in terms of clinical or biological specifications to be respected by means of adapted quality control plans [4][5][6][7]. Uncertainty of measurement, moreover, depends upon the concentration of the analyte to be assayed, which raises problems when the measurand is intended to shed light on several clinical or biological questions [8].…”

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

“…In addition, the EQA design should enable devicespecific and procedure-specific evaluation of results. A description of how these requirements can be met is given in a pilot study report (44,45).…”

Establishment of Reference Range for Serum Creatinine by IDMS and NIST SRM 967 Traceable Calibrator in Government Kilpauk Medical College Hospital Laboratory

“…The term "standardisation" encompasses the reference measurement procedures and reference materials required to achieve comparability of patient test values between different clinical assays [6]. This also ensures the traceability of results to an accepted reference measurement system with greater certainty that a result is close to the "true value [3,7,8].…”

“…Foremost among the laboratory's problems is the poor comparability of analytical results that originate from different laboratories using different methods [6][7][8],and these differences restrict the use of a common reference interval for a particular analyte worldwide. Reference intervals for healthy subjects are very important for the clinical interpretation of laboratory test values [10], especially for the substances which are used as markers of certain diseases.…”