Rapid testing for respiratory viruses: Impact on antibiotic use and time to patient discharge.

Background: Influenza-like illness is often caused by respiratory viral infections, and is a frequent cause of presentation to hospital. Rapid diagnostics for respiratory viruses, with turnaround times of less than sixty minutes, are increasingly available. Early physician knowledge of positive respiratory virus tests has previously been shown to impact patient care in a paediatric population but hasn't been evaluated in adults.

Methods: Rapid testing for the respiratory viruses Influenza A, Influenza B and respiratory syncytial virus (RSV) was introduced in our institution in 2018. This reduced turnaround time for tests from more than 24 h, to 1-10 h depending on time of day. A retrospective cohort study was performed on patients presenting with influenza-like illness, in whom a nasopharyngeal swab for respiratory viruses was requested. Data was collected before and after the introduction of the rapid assay. Outcomes included antibiotic use (less or more than 24 h) and length of hospital stay (less or more than 24 h).

Results: In all patients who tested positive for a respiratory virus, there was an association between rapid testing and less antibiotic use. This was largely driven by paediatric cases; there was no change in prescribing for adult patients. There was no impact on timing of patient discharge.

Conclusions: Rapid testing for respiratory viruses has a potentially useful role in antimicrobial stewardship. It is unclear why earlier knowledge of positive viral test didn't lead to less antibiotics in adults. This study showed no impact of rapid testing on time to patient discharge.