The investigation determined that a discordant negative vitros anti- sars-cov-2 total results were obtained from three patient samples processed using vitros cov2tot reagent lot 0220 on a vitros 3600 immunodiagnostic system.An assignable cause was not determined.The patients had all previously tested pcr positive approximately 2-4 weeks prior to vitros testing.It would be expected that the vitros cov2tot would be reactive as this assay detects the presence of igm, iga, and igg antibodies.No additional testing was performed to confirm or rule out the presence of an interferent in these patient samples.A review of historical quality control results for vitros cov2tot lot 0220 indicates acceptable performance and a reagent issue is not a likely contributor to the event.Additionally, ongoing tracking and trending of complaint data has not identified any signals to suggest there is a systemic quality issue with vitros cov2tot reagent lots 0220.Unexpected instrument performance is not a likely contributor to the events.However, it cannot be entirely ruled out as a contributing factor as precision testing to assess instrument performance was not performed by the customer when requested.The customer provided no information concerning the sample collection device used to collect the affected samples or sample processing of the affected samples.Therefore, pre-analytical sample handling cannot be ruled out as a potential contributor to this event.(b)(4).
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