The initial reporter stated they received discrepant results for one patient sample tested with the following assays on two cobas 8000 e 602 module analyzers: the elecsys tsh assay, the elecsys tsh assay ver.2, elecsys ft3 iii, the elecsys ft4 iii assay, the elecsys anti-tshr immunoassay, and the elecsys anti-tshr ver.2 immunoassay.This medwatch will cover the ft3 assay.Refer to the medwatches with the following.Patient identifiers for information related to all other assays: (b)(6).Refer to the attachment for all patient sample data.The sample was collected on (b)(6) 2020 and run five times on the customer's e 602 analyzer on (b)(4) 2020.The sample was also diluted x2 and repeated for tsh and tsh v2 on the customer's e 602 analyzer.The sample was repeated on an abbott architect analyzer.The sample was also provided for investigation, where it was tested on a second e 602 analyzer on (b)(6) 2020.The serial number of the customer's e 602 analyzer is (b)(6).The ft3 reagent lot number and expiration date used on this analyzer is unknown.The serial number of the e 602 analyzer used for investigation is (b)(4).Ft3 reagent lot number 473372, with an expiration date of may 2021 was used on this analyzer.
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Investigations of the sample were able to reproduce the results obtained by the customer.The sample did not contain an interfering factor against the streptavidin component of the assay.Further measurements of the sample determined that it contains a biotin concentration of approximately 500 ng/ml.The high concentration of biotin can explain the discrepant values generated with the tsh, anti-tshr, ft3, and ft4 assays as the concentration exceeds the maximum threshold for biotin allowed for these assays.Tsh v2 and anti-tshr v2 have a higher biotin tolerance and are not affected.The results generated with these assays can be expected to be correct.Product labeling for ft3 indicates: the assay is unaffected by biotin at concentrations < 70 ng/ml."samples should not be taken from patients receiving therapy with high biotin doses (i.E.> 5 mg/day) until at least 8 hours following the last biotin administration".
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