Investigation: a potential false positive v.Cholerae result on the biofire gi panel was reported after testing a patient stool sample in cary blair media on february 22, 2024.There was no growth of v.Cholerae from culture.Additionally, confirmatory pcr serotyping was also performed and did not detect for v.Cholerae.Due to the biofire gi panel result, the patient had to be isolated and treatment for v.Cholerae was administered.No serious injury or death was reported.Conclusion: the investigation determined that the most likely cause of the discrepant v.Cholerae result was the presence of non-viable organism/nucleic acid in the cary blair transport media.While cary blair medium vials are autoclaved and routinely quality controlled for sterility, non-viable organisms or nucleic acids can remain in the transport medium after the sterilization process.The presence of non-viable organisms and nucleic acid does not compromise the intended use of transport medium, transportation and preservation of clinical stool and rectal specimens; however, the biofire gi panel does not distinguish between nucleic acid from viable or non-viable organisms.The "laboratory precaution" and "limitation" sections of the filmarray gi reagent instruction booklet (https://www.Online-ifu.Com/iti0030) outlines the potential for false positive detections during molecular testing with sterile cary blair transport medium containing detectable levels of non-viable organisms and/or nucleic acid.Importantly, results from the biofire gi panel are intended to be correlated with the clinical history, epidemiological data, and other data available to the clinician evaluating the patient.Detection of organism targets does not imply that the corresponding organisms are infectious or are the causative agents for clinical symptoms.Clinical performance: according to table 11.Biofire gi clinical performance summary of the filmarray gi reagent instruction booklet, the performance claim for the v.Cholerae assay compared to stool culture with standard manual/automated microbiological/biochemical identification showed a specificity of 99.9% (95% ci 99.6-100%).V.Cholerae was detected in the single false positive specimen using bi-directional sequence analysis.To supplement the prospective data, an evaluation of contrived specimens was performed.According to table 18.Biofire gi panel performance using contrived specimens of the filmarray gi reagent instruction booklet, the performance claim for v.Cholerae showed a positive percent agreement (ppa) of 84.6% (95% ci 73.5-92.4%) and a negative percent agreement (npa) of 100% (95% ci 96.7-100%).Ten of the contrived specimens were spiked with an isolate which was found to have a highly divergent toxr gene that was not present in the ncbi database and non-reactive with the biofire gi panel v.Cholerae assay.The biofire gi panel vibrio assay was positive for nine of these specimens.
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Summary: lancet lab (bloemfontein, south africa) reported a potential false positive vibrio cholerae result on the biofire® filmarray® gastrointestinal (gi) panel after testing a patient stool sample.Due to the biofire gi panel result, the patient may have received inappropriate treatment and also had to be isolated.The investigation determined that the most likely cause of the discrepant v.Cholerae result was the presence of non-viable organism/nucleic acid in the cary blair transport media.
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