English
Background
The U.S. FDA’s guidance for industry and staff titled “Assay Migration Studies for In Vitro Diagnostic Devices”1 provides a least burdensome approach for the transfer of previously-approved assays from an existing to a new system. This approach enables the use of rigorous analytical performance data in place of full clinical data to implement a cleared product on a new platform. The Beckman Coulter DxI 9000 Access Immunoassay Analyzer† includes numerous updates and new features designed with a goal to improve laboratory workflows and provide quality results to support patient management. Such elements include improved pipetting capabilities, updated process monitoring, increased throughput, reliability enhancements, and software features focused on the needs of the operator. The analyzer also utilizes a new alkaline phosphatase substrate reagent that provides reduced time to result for every test as well as other benefits including improved signal-to-noise and reduced sensitivity to endogenous alkaline phosphatase interference. The existing menu of Beckman Coulter Access reagents is being transferred to this system. Data herein summarize results from analytical studies described within the assay migration guidance and obtained during verification testing of assays for cardiac troponin (hsTnI) and alpha-fetoprotein (AFP) on the DxI 9000 Access Immunoassay Analyzer.
Methods
Analytical studies for quantitative assays were performed as directed by the assay migration guidance to compare performance of the Access hsTnI and Access AFP assays across the current Access 2 and new DxI 9000 Access Immunoassay Analyzers.. A comparison study was performed on a panel of >180 samples across multiple sites to assess the equivalence of results from the two platforms through regression and bias analyses based on CLSI guideline EP09c, 3rd ed.2 and comparison to zones of allowable total difference (ATD) calculated based on each assay’s variability on the Access 2 Immunoassay analyzer. Within-laboratory precision and reproducibility were evaluated following CLSI EP05-A3.3 Performance at low analyte levels was evaluated following CLSI EP17-A2.4 Linearity was evaluated following CLSI EP06-Ed2.5
Results
Comparison studies for the Access hsTnI assay yielded 96.8% (90% CI: 95.5% - 97.8%) of all lithium heparin plasma results within the predetermined ATD zone. Comparison studies for the Access hsTnI assay yielded 97.1% (90% CI: 96.0% - 98.1%) of all serum results within the predetermined ATD zone. Comparison studies for the Access AFP assay yielded 99.7% (90% CI: 99.2% 100%) of all serum results within the predetermined ATD zone. All estimated results including 90% CI met expectations detailed in FDA’s assay migration study guidance. Other analytical studies yielded comparable performance for both assays across the existing and new platforms that met product design requirements.
Conclusions
The data herein present an exercise of the U.S. FDA assay migration guidance applied to two assays from the Beckman Coulter Access menu. Individual assay data generated for the Access hsTnI and Access AFP assays on the DxI 9000 Access Immunoassay Analyzer† in this study met study design criteria.
