Is Rapid Respiratory Virus Testing Fast Enough to Affect Antibiotic Prescribing?

Rapid respiratory virus test results for children in an emergency department could be received too late to inform antibiotic prescribing.

Implementing rapid respiratory virus testing for children in an emergency department (ED) did not reduce the high rate of antibiotic prescribing for “influenza-like" illness (ILI), despite that reduction hypothesized by study investigators.

“Identification of the respiratory pathogen provides an opportunity to guide the evaluation and management of children with acute respiratory infection, with the potential to decrease antibiotic use, resource use, and health care costs,” explained Suchitra Rao, MBBS, MSCS, Department of Pediatrics Infectious Diseases and Epidemiology, University of Colorado School of Medicine, Aurora, CO, and colleagues.

“We hypothesized that there would be a decrease in antibiotic prescribing in the group in which results of rapid respiratory pathogen testing (RPT) were reported to the clinician,” Rao and colleagues indicated.

The investigators compared antibiotic prescribing for 452 children with ILI and for whom RPT results were available, to the prescribing for 456 children with similar demographic and clinical characteristics but without RPT testing. The children (median age 2.1 years) were evaluated at the ED between December 2018 to November 2019 for ILI with symptoms including fever, and at least 1 of the following: cough, sore throat, runny nose, or nasal congestion.

In addition to the primary study outcome of antibiotic prescribing, as intravenous or enteral antibiotics administered during the ED visit or hospitalization or as outpatient prescription, the investigators ascertained antiviral prescribing, ED length of stay, hospital admission, recurrent ED visits, number of health care visits within 10 days of the index visit, diagnostic tests ordered and patient/family acceptance of testing.

The RPT testing in the intervention group was performed on samples from nasopharyngeal swabs on the BioFire FilmArray RP2 Panel (BioFire Diagnostics), which has an average turnaround time of 45 minutes. Clinicians had the discretion to order RPT testing for any patient from the central clinical laboratory, which used the BioFireRP, GeneXpert, or Cepheid systems, and provided results in approximately 2 hours.

Rao and colleagues reported that, in their initial analysis, children in the intervention group were more likely to receive antibiotics than those in the control group (relative risk [RR], 1.31; 95% CI 1.03-1.68); but also to have a diagnosis in which antibiotics would be indicated (risk difference, 8.6; 95% CI, 3.2-13.8).In the adjusted intention-to-treat analysis, the difference in antibiotic prescribing rates between groups was not significant. Those in the intervention group were found more likely to receive appropriate antivirals, however, and to have longer ED length of stay and higher rates of hospitalization.

The investigators acknowledged that the reason for high antibiotic prescribing for ILI despite availability of rapid respiratory virus testing "is unknown." They note, however, that in 2 other studies of RPT without decreased antibiotic prescriptions were often provided at completion of the clinical evaluation before RPT results were available. In addition, they report their own survey finding that acceptance of RPT was higher if test results could be available in 20 minutes.

"Based on our clinician and caregiver survey data as well as our other study findings, the 45-minute turnaround time for respiratory testing may be too long to impact ED provider clinical decision making, and the impact of platforms with a shorter turnaround time should be the subject of future study," Rao told Contagion.

Rao and colleagues concluded "there is a limited role for RRP pathogen testing in children in this setting."