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Intended use: vitek® ms is a mass spectrometry system using matrix-assisted laser desorption/ionization time 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 mould infections.The vitek® ms system is intended for laboratory use by healthcare professionals who are trained in microbiology and good laboratory practices.Incident description: a customer in france reported to biomérieux that they obtained delayed results >24 hours (and potential identification issue) with the product vitek ms instrument (ref.410895, serial number (b)(4)) regarding three patient isolates.According to the vitek ms reports provided by the customer, a "no identification" result was obtained for three isolates associated with three different patients.The customer did not perform any other identification methods, but indicated she will retest the strains and provide the results.Although there is no evidence of a vitek ms malfunction, the customer reported delayed results >24 hours compared to their standard protocol time frame to deliver identification results.There is no indication or report from the customer that this event led to any adverse event related to the patient's state of health.An investigation has been initiated.
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A customer in france notified biomérieux that they obtained results delayed >24 hours (and potential identification issue) in association with their vitek® ms instrument (ref.410895, serial number (b)(6) ) regarding three patient isolates.Investigation fine tuning: according to vilink alert tool criteria, no fine tuning was needed for tests made on (b)(4) 2021.However, fine tuning was at the limit for tests made on (b)(4) sep 2021.A new fine tuning was made on (b)(4) 2021.The fine tuning indicators acceptance criteria could be affected by the non-optimal fine tuning made prior to the misidentification and by the quality of the calibrator spot preparation.In these conditions, the vilink alert tool might not reflect the real status of the system.Good fine tuning and good calibrator spot preparation are a prerequisite for monitoring the system using the vilink alert tool.Spot preparation quality: the calibrator and sample ¿all peaks¿ values are quite heterogeneous, indicating that spot preparation was not optimal.Knowledge base (kb) review: the information provided by the customer suggests that the organism identifications are: - id #122108300621(benoist) = acidaminococcus intestini - id #152109020401 (dovi) = comamonas spp.Acidaminococcus intestini is not present in vitek ms kb v3.2 and only two comamonas species are present in the vitek ms kb v3.2.Based on the information provided, the expected identifications are unknown because no reference identification method was used to confirm the id.Sample data analysis: reprocessing the customer data with vitek ms kb v3.2, spectra led to "no identification" results for all tests.Then, as an exercise, processing the customer data with next vitek ms kb v3.3 in development, spectra led to "no identification" results for lab id (b)(4) (dovi) and lab id (b)(4).For lab id (b)(4) (benoist), all tests led to single choice of acidaminococcus intestini.Repeating the process again using saramis ruo database (reference spectra), spectra led to "no identification" results for lab id (b)(4).Id# (b)(4)(benoist) all tests led to single choice of acidaminococcus intestini.Id# (b)(4) (dovi), all tests led to single choice of comamonas spp.For two isolates, lab id (b)(4)(dovi) and lab id (b)(4) (benoist), the same results were obtained for tests made before and after the new fine tuning.It was not possible to do this comparison for third lab id (b)(4) because the sample was not available.When ¿no identification¿ results are obtained, the customer should follow the process described in the vitek® workflow user manual 4501-2233 - f : ¿repeat the acquisition for the same deposit.If the message is displayed again, redo the deposit and then the acquisition.If the message is displayed again, repeat the identification using another method (such as vitek® 2, api strip, other biochemical or molecular methods).Conclusion the cause of the customer¿s issue is a combination of a known system limitation regarding spectra for species not included in the vitek® ms knowledge base (v3.2 and v3.3) along with non-optimal spot preparation.In addition, the following system limitation is mentioned in the vitek® ms v3.0 knowledge base user manual ref.161150-556-b: ¿* testing of species not found in the database may result in an unidentified result or a misidentification.* interpretation of results and use of the vitek® ms system require a competent laboratorian who should judiciously make use of experience, specimen information, and other pertinent procedures before reporting the identification of test organisms.Additional information known to the user, such as gram stain reaction, colonial and cellular morphology, and growth aerobically or in co2 should be considered when accepting vitek® ms results.¿ local customer service provided the customer with additional training materials to help improve their spot preparation technique.Customer service also provided information regarding vitek® pickme¿ (ref 423551/ 423546) to help with sample spot preparation.Lastly, customer service suggested the customer perform a new fine tuning that ensures all of the mandatory acceptance criteria are met.
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