Efficient use of the BioFire® FilmArray® Meningitis/Encephalitis Panel: a diagnostic stewardship approach

Background The BioFire® FilmArray® Meningitis/Encephalitis Panel (FA/ME) (BioFire Diagnostics, LLC, Salt Lake City, UT, USA) is a multiplex polymerase chain reaction (PCR) assay which detects pathogens causing community‐acquired meningitis/encephalitis. Aims This study aimed to evaluate the performance, clinical impact and potential of a diagnostic stewardship algorithm to optimise FA/ME use in an Australian tertiary hospital. Methods This retrospective study evaluated microbiological data from 712 patients who underwent FA/ME testing between July 2018 and April 2024 at the Royal Melbourne Hospital and clinical data from a subset of 439 patients. Results The FA/ME positivity rate was 12.2%. The panel showed 69.70% sensitivity and 93.04% specificity compared with comparator methods. FA/ME positivity was associated with targeted antimicrobial therapy and shorter hospital stays. The cerebrospinal fluid white cell count (WCC) strongly predicted FA/ME positivity (area under the curve = 0.80, P < 0.0001). Conclusions A diagnostic stewardship algorithm employing a WCC threshold of >50 × 10 6 /L for FA/ME testing, with reflex testing of specimens with lower WCC on an alternative viral multiplex PCR, would have reduced annual costs from $23 302 (without stewardship) to $14 646, doubled the positivity rate to 29.54% and detected all clinically significant infections. This study provides insights into optimising FA/ME use in Australia to improve patient management.