The investigation has determined that a higher than expected ammonia (amon) result was obtained from an american proficiency institute proficiency sample and a lower than expected result was obtained from a vitros liquid performance verifier processed using vitros chemistry products amon slides lot 1018-0253-9365 on a vitros 350 chemistry system.A definitive assignable cause of the events could not be determined.Continual tracking and trending of complaint data has not identified any signals to suggest there is a systemic quality issue with vitros amon reagent lot 1018-0253-9365.A possible cause of the events is an issue related to a suboptimal calibration.The calibration parameters for the calibration event on (b)(6) 2020 were determined to be atypical compared to the database values.The historical quality control results following the calibration event were not acceptable.The higher than expected proficiency sample result was also obtained using the parameters from this calibration event.The cause of the suboptimal calibration is unknown.However, a possible cause of the suboptimal calibration could be related to improper fluid preparation and handling protocol as the customer stated that new technicians had been training around the timeframe of the events and that there were concerns of user error having occurred.Another possible overall cause of the events is user error.The customer stated that at the time of the events, there were concerns of possible improper protocol as new technicians were being trained.Additionally, the customer did not initially report the attainment of the higher than expected proficiency result to ortho as they believed the issue was likely related to user error.As historical qc results were not acceptable a vitros amon lot 1018-0253-9365 related issue cannot be ruled out as a contributing factor of the event.Precision testing was not performed on the vitros 350 chemistry system at the time of the events and historical qc results were imprecise.Therefore, an instrument related issue cannot be confirmed nor ruled out as a contributing factor of the events.(b)(4).
|