Commercial multiplex PCR testing for respiratory pathogens has increasingly become available in recent years. However, the impact of introduction of expensive testing should be evaluated. This audit evaluated the reporting times for respiratory pathogen testing by FilmArray RP2, reviewed the indications for testing, and assessed the potential impact of the assay on antimicrobial stewardship.
Materials and methods
Nose and throat swabs were tested by FilmArray RP2 on a daily basis. A subset of results with positive RP2 results was selected for clinical review by a microbiologist, and recommendations of antimicrobial therapy were made. A second review of electronic charts was performed 1 day after the final result was released to assess changes to antimicrobial usage.
110 results were available for data analysis. Most testing was performed within 2 days of admission to hospital (n=95, 86.3%) and 88.2% of preliminary RP2 results were available within 3.9 hours of sample receipt in the laboratory. Frequently detected pathogens included Rhino/Enterovirus (n= 34, 30.9%), Influenza A (n=19, 17.2%) and parainfluenza virus 3 (n=15, 13.6%). The most common diagnoses for patients included pneumonia (n=21, 19.1%), asthma (n=10, 9.1%), unspecified lower respiratory tract infection (n=8, 7.3%) and chronic obstructive airways disease (n=7, 7.3%). Seventy-six (69.1%) patients were on one or more antimicrobials at the time of RP2 test reporting. A total of 50 recommendations were made on the test report (stop antibiotics n=21, 42%; review antibiotics n=12, 24%; review tetracyclines n=6, 12%, others n=11, 22%). No change was made to the antibiotic regime for 28 patients (56%).
Filmarray RP2 allows testing and reporting of respiratory pathogens in the early stages of hospital admission. The indications for respiratory pathogen testing appear to be varied, and appropriateness criteria should be formulated. Many patients were on antimicrobials at the time of test reporting, and half of patients continued on antimicrobials despite a recommendation to stop or review treatment.