The investigation determined that reproducible, discordant vitros anti- sars-cov-2 igg results were obtained from a single patient sample when processed using vitros cov2igg reagent lot 0120 on a vitros xt7600 integrated system.A definitive assignable cause for the discordant reactive results could not be determined with the information provided.Based on historical quality control results, a vitros cov2igg reagent performance issue is not a likely contributor to the event as all qc fluid results were within the correct ifu interpretation region.Additionally, there is also no indication of any instrument malfunction and unexpected instrument performance is not a likely contributor to the event.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.In addition, it was not possible to establish if the customer is following the sample collection device manufacturer¿s recommended centrifugation protocol; therefore, pre-analytical sample processing cannot be ruled out as a contributing factor.It is possible that cellular debris, due to poor sample preparation, was present in the affected samples, although this could not be confirmed.The patient that produced the discordant vitros results had not previously tested positive for covid-19 infection and was not known to have an active covid-19 infection at the time of testing.The most likely cause of the discordant results in this case is the vitros cov2igg test generated false positive results for the sample under test.The vitros cov2igg ifu does not preclude the possibility of false positive cov2igg results due to cross-reactivity from pre-existing antibodies or other possible causes.Continual tracking and trending of complaints has not identified any signals that would point to a potential systemic issue with vitros cov2igg lot 0120.
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