(b)(6) customer contacted the siemens customer care center to report elevated immulite 2000 xpi br-ma (ca15-3) results obtained on one patient sample.The results were considered discordant compared to alternate method testing.Quality control (qc) was in expected ranges.The customer tested the sample for the presence of heterophilic antibodies with scantibodies hbt and performed a dilution study.Siemens has concluded the investigation for this event.The customer observed a potential falsely elevated immulite 2000 xpi br-ma (ca15-3) (l2kbr) result on a patient that was low/negative on an alternate ca15-3 method.Siemens reviewed the available information to determine probable cause and evaluate for a potential product issue.Qc was in range at the time the results were generated, indicating this is a patient/sample specific incident.The result in the alternate test method, while below the diagnostic cut off of <28.5 u/ml, was close to the cutoff at 26.5 u/ml.The elevated sample was run with serial dilutions and treated with scantibodies hbt for the presence of heterophilic antibodies.The results after these treatments did not lower to below the 46.8 u/ml.According to the expected values section of the instructions for use (ifu), 46.8 u/ml is the 95th% value observed for healthy post-menopausal women.This is suggestive of no interfering substance in the sample however immunoassays are subject to a number of interferences.Interferents may not necessarily be due to an interfering antibody, but may be due to other exogenous interferences such as drugs, nutritional supplements and/or herbal medicine in the blood.This cannot be ruled out.The ifu states that "ca15-3 antigen levels in a given specimen determined with assays from different manufacturers can vary due to differences in assay methods and reagent specificity.Results reported by the laboratory to the physician must include the identity of the assay used to measure ca15-3 antigen levels.Values obtained with different assays cannot be used interchangeably.Before changing assays, the laboratory must confirm baseline values for patients being serially monitored." (intended use section)."elevated levels have also been found in patients with lung cancer (63%) and ovarian cancer (80%)." (summary and explanation section).This is a potential cause of the elevated result since elevated levels of ca15-3 can also be observed in several conditions other than breast cancer.Per the limitation section of the ifu, "for diagnostic purposes, the results obtained from this assay should always be used in combination with the clinical examination, patient medical history, and other findings." based on the investigation, no product problem was identified.The customer is operational.No further investigation in required.Mdr 1219913-2022-00055 was filed for the same issue.
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A customer obtained an elevated immulite 2000 xpi br-ma (ca15-3) result on a patient sample (above reference range result).The result was reported to the physician, who questioned the result.The sample was sent to another site and was retested with an alternate method and a lower result was obtained (within reference range result).The initial elevated result was considered discordant compared to the alternate test method result.The sample was sent back to the customer site and was retested on the same immulite 2000 xpi instrument.An elevated result was obtained (above reference range result).The result from the alternate method was considered to be correct.There are no known reports of patient intervention or adverse health consequences due to the discordant, falsely elevated ca15-3 result.
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