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Hold gn 12-15
summary: a publication by rule et al.Titled "diagnostic accuracy of the biofire filmarray blood culture identification panel when used in critically ill patients with sepsis" contained information regarding potential false negative enterobacterales and klebsiella pneumoniae detections on the filmarray blood culture identification (bcid) panel after testing a sample from a (b)(6), female patient.Due to the filmarray bcid panel result, the patient's antibiotic therapy was delayed for 43.25 hours.While investigating this result, biofire became aware that the patient ultimately died, and it was unknown to the author if the filmarray bcid panel contributed to the patient's death.Based on the limited information provided, the investigation determined that the customer was not interpreting the results of the filmarray bcid panel in conjunction with the gram stain results as is intended.A likely cause for the k.Pneumoniae and enterobacterales discrepancies is sample-handling error.Reference: rule r, paruk f, becker p, et al.Diagnostic accuracy of the biofire filmarray blood culture identification panel when used in critically ill patients with sepsis.J microbiol methods.2021;189:106303.
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Investigation: during a scientific literature review, biofire came across a publication titled "diagnostic accuracy of the biofire filmarray blood culture identification panel when used in critically ill patients with sepsis." in this publication, it was alleged that erroneous results were received on the filmarray bcid panel when testing patient samples.Biofire reached out to the author for additional information and was informed that a potential false negative enterobacterales and k.Pneumoniae result on the filmarray bcid panel delayed treatment for one patient, and the patient later died.Details of this incident have been outlined below: on an unknown date, a (b)(6), female, (b)(6) patient was admitted to the (b)(6) hospital in (b)(6).Clinical signs and symptoms are unknown.No treatment was initiated before testing.A blood sample was collected and cultured in a bact/alert® fan® aerobic plus bottle (date of collection unknown).The blood culture sample was tested on the filmarray bcid panel 7.66 hours (460 minutes) after the bottle flagged positive.The filmarray bcid panel reported all analytes as not detected (run file is not available).The same sample was used to perform a gram stain, and both plump gram negative bacilli and palisading gram positive bacilli were observed (date of testing unknown).The same sample was again used to perform routine microscopy and susceptibility testing, and these tests indicated growth for k.Pneumoniae and corynebacterium spp (date of testing unknown).The author of the publication reported that the negative filmarray bcid panel result caused antibiotic therapy to be delayed for 43.25 hours (2595 minutes) until the gram stain result was communicated to the physician.Please note that biofire considers this to be off-label use as filmarray bcid panel results are intended to be interpreted in conjunction with gram stain results (filmarray bcid panel instruction booklet [rfit-prt-0369]).The author stated that once the gram stain result was reported, the patient was started on imipenem.When asked the outcome of the patient, the author stated that the patient ultimately died.When asked if the delay in treatment caused the patient to deteriorate, the author responded "i cannot formally conclude on this as i conducted this study from the laboratory side.I was not the primary treating physician in this case.The delay in appropriate treatment may have contributed to this patient's demise." no run file, pouch lot#, or instrument serial# was provided.In the last year, field reports of potential false negative enteric and k.Pneumoniae detections were both observed at a rate of <0.001.The filmarray bcid panel is observed in the field to be performing within specification.Conclusion: based on the limited information provided, the investigation determined that the customer was not interpreting the results of the filmarray bcid panel in conjunction with the gram stain results as is intended.A likely cause for the k.Pneumoniae and enterobacterales discrepancies was determined to be sample handling error.The filmarray bcid panel is a qualitative, multiplexed, nucleic-acid-based in vitro diagnostic test intended for use with filmarray systems.It is capable of simultaneous detection and identification of multiple bacterial and yeast nucleic acids and select genetic determinants of antimicrobial resistance and is performed directly on blood culture samples identified as positive by a continuous monitoring blood culture system.The publication author indicated that no targets were detected on the filmarray bcid panel after testing the patient sample, whereas gram stain identified both plump gram negative bacilli and palisading gram positive bacilli, and culture had growth for k.Pneumoniae and corynebacterium spp.It was noted that these false negative results affected patient care due to a 43.25 hour (2595 minutes) delay in assessment of antibiotic therapy choices and that imipenem was started only after the communication of the gram stain result.The limitations section of the filmarray bcid panel instruction booklet [rfit-prt-0369] states that filmarray bcid panel results are intended to be interpreted in conjunction with gram stain results and in some cases, the gram stain result and results of the filmarray bcid panel may be discrepant (e.G.Detection of gram-positive cocci by filmarray bcid panel when gram-positive cocci were not observed in the gram stain).In these cases, the filmarray bcid panel results should be confirmed (e.G.By culture) before reporting, unless the result is concordant with other laboratory, epidemiological, or clinical findings.The detection of nucleic acid targets is dependent upon proper sample collection, handling, transportation, storage, and preparation.As indicated in the "procedure" section of the filmarray bcid panel instruction booklet [rfit-prt-0369], the sample buffer ampoule should be squeezed into the red-capped sample injection vial (seated in the loading block) prior to adding 0.2 ml of blood culture sample.The loaded sample injection vial should then be inverted gently at least three times to mix before adding it to the pouch.No run files were provided for analysis, however, it is possible that not enough sample was injected into the pouch, or that the sample was not inverted properly prior to injection into the pouch.Failure to observe proper procedures in any one of these steps can potentially cause false negative values.Performance data: according to table 22 of the filmarray bcid panel instruction booklet [rfit-prt-0369], the performance claim for the k.Pneumoniae assay compared standard manual/automated microbiological/biochemical identification showed a sensitivity/positive percent agreement (ppa) of 97.1% (95% ci 91.9-99.4%) and a specificity/negative percent agreement (npa) of 99.6% (95% ci 99.2-99.8%).Sensitivity and specificity refer to performance with the prospective specimens only; ppa and npa refer to performance with the seeded specimens.The isolate from one false negative k.Pneumoniae specimen was identified as the closely related organism, raoultella planticola and not k.Pneumoniae.6/9 false positive k.Pneumoniae results appear to be due to cross-reactivity with enterobacter aerogenes and raoultella ornithinolytica (misidentified as k.Oxytoca by phenotypic methods).Also outlined, the performance claim for the enterobacteriaceae assay compared standard manual/automated microbiological/biochemical identification showed a sensitivity of 98.4% (95% ci 96.9-99.3%) and a specificity/npa of 99.8% (95% ci 99.4-99.9%).Again, sensitivity and specificity refer to performance with the prospective specimens only; ppa and npa refer to performance with the seeded specimens.One false positive and one false negative enterobacteriaceae were consecutively tested specimens and may be due to sample mix-up.One isolate from another false negative specimen, identified as e.Coli by phenotypic methods, was identified as pasteurella, and not e.Coli, by bidirectional sequencing (filmarray bcid panel instruction booklet [rfit-prt-0369).Notes: corynebacterium is an off-panel organism and it is noted to be a part of a group of organisms commonly considered to be blood culture contaminants.A negative filmarray bcid panel result does not exclude the possibility of bloodstream infection and should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.Reference: rule r, paruk f, becker p, et al.Diagnostic accuracy of the biofire filmarray blood culture identification panel when used in critically ill patients with sepsis.J microbiol methods.2021;189:106303.
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