Product description: vitek® ms is a mass spectrometry system using matrix-assisted laser desorption/ionizationtime of flight mass spectrometry (maldi-tof ms) for the identification of microorganisms cultured from human specimens.The vitek® ms system is a qualitative in vitro diagnostic device indicated for use in conjunction with other clinical and laboratory findings to aid in the diagnosis of bacterial, yeast and mold infections.Complaint description: a customer in the united states complained after having obtained what they described as an incorrect identification test result when testing a microoganism isolated from one patient's sample with their vitek® ms (ref 410895).The customer reported that on (b)(6) 2023, they had tested a colony isolated from a patient's sample using their vitek ms system and that the strain was identified as brucella spp.With 83.6 confidence value.The customer said that on the same day they had rerun of the sample and that the strain was identified as escherichia coli with 99.9 confidence value.The customer said that based on culture and isolation testing the microoganism is escherichia coli.No further detail were provided.There is no indication or report from the customer that this event led to or contributed to any death, serious injury, or serious deterioration in the state of health for the concerned patient.
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Following the potential incorrect identification of e coli as brucella reported by the customer an investigation has been carried out at biomérieux manufcturing site.No reference method was used by the customer to confirm the identification of the concerned microorganism.Thus expected identification is unknown.Complaint trend analysis and device history record was perfomed and no general trend has been identified.There is no capa, nor non conformity on vitek ms linked with customer 's complaint.According to the vilink alert tool criteria, the fine tuning status was good at the time of acquisition.During the analysis of the spot quality preparation, it has been observed that there was a high variability of the calibrator ¿all peaks¿ values between 35 and 126 peaks.The low the customer¿s spot preparation quality was not optimal.The calibrator and sample ¿all peaks¿ values were heterogeneous.Analysis of mzml sample files provided by the customer, showed that that the spectra (j3) which gave the misidentification to brucella spp have the lowest number of peaks (35 peaks) which is near the acceptable limit for giving an ¿identification¿ result or a ¿no identification¿ result (30).Moreover, this misidentification was obtained with a low identification score (-0.29) which is near the acceptable limit for giving an ¿identification¿ result or a ¿no identification¿ result (-0.4).This could be explained by a non-optimal spot preparation of the sample strain.By reprocessing the customer data with vitek ms kb v3.3, spectra which gave misidentification results as brucella spp led to no identification.The issue reported by the customer could not be reproduced.The root cause of the mis-identification result observed by the customer is most probably associated with non optimal spot preparation and knwoledge base (kb) weakness linked with the bad quality of spectra.
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