The customer no longer has either sample to retest.The sample tube type would normally be serum separator tube.The customer is not certain if the primary tube was placed on the system for testing or if the sample was poured and aliquoted for testing.The customer reports the samples were drawn at a drawing site and the samples are normally centrifuged at the drawing site and would not have been re-centrifuged in the laboratory.The customer reports that the patient has declined being re-drawn and re-tested for (b)(6).It is unknown if the patient was vaccinated for (b)(6).The customer declined customer service engineer (cse) dispatch at this time.The (b)(6) quality control (qc) has been performing in range without issue.The cause for the discordant (b)(6) results is unknown.Siemens healthcare diagnostics is investigating.The ifu states in the interpretation of results section: "results should always be interpreted in conjunction with the patient's medical history, clinical presentation, and other findings.".
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Siemens filed the initial mdr 1219913-2020-00127 on (b)(6) 2020.(b)(6) 2020 correction: in the intial mdr report section h4, typographical error for the device manufacture date.The correct date is (b)(6) 2019 (b)(6) 2020 additional information: the customer had a patient sample that recovered reactive (17.39 miu/ml) with advia centaur xp anti-hbs2 (ahbs2) lot 120 but when a new sample from the patient was tested 4 days later it was nonreactive (4.35 miu/ml) with lot 120.The patient declined to be redrawn and retested.The samples were not tested with any other hepatitis b assays.The customer was not able to provide the patient's medical status or a list of medications/supplements the patient is taking.There is no sample that can be sent to siemens for evaluation.The samples were drawn in serum separator tubes, centrifuged off site, and would not have been re-centrifuged when received in lab.Siemens reviewed the calibration and control data provided and there is no evidence of a problem.The original sample was not tested on another analyzer before being tested on the advia centaur xp.The comparison of results section of the advia centaur xp anti-hbs2 instructions for use (ifu) (10698735 revision k, 2019-08) lists the 95% confidence interval (ci) for negative percent agreement as 96.7% - 98.5% and the 95% ci for positive percent agreement as 96.7% - 98.7% so a certain number of false positives and false negatives can be expected.The cause of the discordant results seen by the customer with samples from this one patient when using advia centaur xp ahbs2 lot 120 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.The instrument is performing within specifications.No further evaluation of the device is required.Section h6, the device, method, results and conclusion codes were updated to reflect the additional information.
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