Clinical utilization and culture concordance of categorical and semiquantitative concentration values on the BioFire® Pneumonia Panel at a major academic quaternary referral center.

Background: Pneumonia mortality can be decreased by early antibiotic administration. Pathogen identification aims to minimize inappropriate, nontargeted antibiotic exposure. Molecular assays expedite organism identification through nucleic acid detection and antimicrobial resistance by screening for genetic markers.

Methods: We evaluated concordance of organism identification, resistance markers, and semiquantitative results between a Food and Drug Administration-approved molecular diagnostic test and traditional culture methods. We performed a retrospective analysis of BioFire^® Pneumonia Panel (PN Panel) orders during a 2-month period.

Results: Organism identification was 97% concordant between paired culture and polymerase chain reaction (PCR) detection. Probability of growth in culture varied proportionally with the "semiquantitative" PN Panel result, with only 4% of organisms with 10⁴ copies/mL growing in culture, versus 53% of organisms with 10⁷ copies/mL growing in culture. Additionally, in 2.5% of cases, the PN Panel identified an organism that did not grow from culture. In comparison, 0.1% of paired organisms were detected by culture but were not seen by BioFire PCR. Concordance of resistance detection with various culture-based methods was 99%.

Conclusion: Combining PN Panel and culture results can maximize early, targeted resistance detection and organism treatment, and the semiquantitative result is a proxy for the probability of growth in culture and the clinical burden of each organism.