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Investigation summary: the complaint investigation for suspected false negative results when using bd max¿ cpo (ref.(b)(4)) kit lot 4325067 was performed by the review of manufacturing records, retain material testing, review of customer¿s data and by the complaint¿s history review.The review of quality control records of bd max¿ cpo lot 4325067 revealed no anomalies that could explain the customer¿s negative results.Customer reported that for one of their samples (last three digits of accession number #571), the bd max¿ result was negative for vim/imp-1-2 targets even though this sample tested positive for vim when cultured, also confirmed by immunochromatography.According to customer, this is an issue with the interpretation of a positive result with the bd max¿ cpo kit lot 4325067.The retain material of bd max¿ cpo from lot 4325067 was visually inspected and showed no anomalies.However, the kit from lot 4325067 had expired at the time of testing, so no conclusion could be drawn regarding its performance.Customer provided one run files for 206 from bd max¿ instrument ct1682 for the investigation.Manual pcr curve adjudication of the sample in position a5 showed no pcr amplification curve, and no anomaly.The expected result in such conditions is negative since the signal did not reach the threshold of ct 10 to 35 and endpoint value above 400 required to be considered valid by the algorithm.As stated in the assay package insert ¿limitations of the procedure¿ section, the bd max¿ system provides qualitative results.Any reported ct value or displayed curve should only be used for the purposes of laboratory quality control trending, research, and public health reporting.A negative result was the expected result in such condition.It must also be noted that limit of detection can vary between different assays and testing methods.Based on the investigation and information provided, no issue is suspected, a sample with a concentration below the limit of detection of the assay is the most likely cause to explain the customer¿s issue.There is no indication of a reagent issue based on the analysis of the complaints received for discrepant results on bd max¿ cpo kit lot 4325067.The root cause was not identified.However, a sample at or near the assay limit of detection (lod) is the most likely cause to explain the customer¿s discrepant results.Bd cannot confirm the complaint based on the investigation that was performed.Bd did not initiate a corrective and preventive action since no new hazard was identified.
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