Siemens filed the initial mdr on june 3, 2020 reporting that the customer observed reproducible elevated results on a patient's sample with the advia centaur xp anti-hbs2 assay.June 4, 2020 - additional information the customer had a sample that recovered reactive (238.4, 247.3, 257.3 miu/ml) with advia centaur xp anti-hbs2 (ahbs2) lot 122 but when it was tested on another advia centaur xp with ahbs2 lot 120 it recovered nonreactive (<3.1, 4.24, 4.32 miu/ml).Other samples tested that day with lot 122 were retested with lot 120 but no other samples had the same issue.All siemens ahbs2 controls following ahbs2 reagent lots 122 and 120 were within normal ranges.The sample was also hbsii reactive (>1000 index), hbct reactive (>8 index), hbeag reactive (>1000 index), and anti-hbe nonreactive (0 index).The sample was from an anorectal surgery patient.The customer was not able to provide a list of medications/supplements the patient was taking.The sample cannot be sent to siemens for evaluation.The clinical sensitivity and specificity section of the advia centaur xp/xpt anti-hbs2 instructions for use (ifu) (10629819, revision l, 2019-08) lists the 95% confidence interval (ci) for resolved relative sensitivity as 98.30% - 100% and the 95% ci for resolved relative specificity as 98.34% - 99.88% so a certain number of false negative and false positive results can be expected for this assay.This one discrepant sample does not indicate a product problem with advia centaur xp ahbs2 lots 120 and 122.A review of internal data indicates advia centaur xp ahbs2 lots 120 and 122 are performing as intended.The cause of the discrepant results seen by the customer with this one patient sample when using advia centaur xp ahbs2 lots 120 and 122 could not be determined, but siemens cannot rule out pre-analytical factors, a sample issue, or normal assay performance.Based on the investigation, no product problem was identified and the customer is operational.Section h6 results and conclusion codes were updated to reflect the additional information.
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