Extended respiratory viral polymerase chain reaction testing may not reduce hospital length of stay or antibiotic use among adult inpatients with respiratory tract infections compared with standard viral testing, according to a retrospective audit conducted at a tertiary hospital in Australia.
In the study, investigators evaluated whether extended respiratory viral (ExRV) polymerase chain reaction (PCR) testing, capable of detecting additional viruses such as rhinovirus, adenovirus, parainfluenza, and human metapneumovirus affected the management of adult patients. The analysis included 941 tests performed between April 1 and August 31, 2024, 330 of which met the criteria for respiratory tract infection or exacerbation.
The investigators categorized the patients into three groups based on viral testing results: no virus detected; positive on standard influenza, respiratory syncytial virus (RSV), and severe acute respiratory syndrome coronavirus (SARS-CoV)-2 testing; or positive only on the extended panel. Outcomes included hospital length of stay and duration of intravenous, oral, and total antibiotic therapy—analyzed using regression models adjusted for clinical covariates.
Across the groups, the extended panel results didn't significantly affect hospital length of stay and antibiotic duration. Among the patients who received antibiotics, adjusted analyses showed no statistically significant differences in intravenous, oral, or total antibiotic duration based on viral testing category. Similarly, no statistically significant difference in length of stay was observed after excluding outliers with prolonged admission because of noninfectious conditions.
In contrast, patients with positive influenza, RSV, or SARS-CoV-2 testing were less likely to receive oral antibiotics or any antibiotics, while intravenous antibiotic use didn't differ statistically. No statistically significant differences were observed between patients with viruses detected only on the extended panel and those with no detected virus.
ExRV PCR testing was positive in 33% (n = 110) of the included cases, with rhinovirus and influenza A being the most frequently detected pathogens. Test timing limited clinical utility, with results available on the day of discharge in 20% of patients and after discharge in 21.5%. The median time in isolation pending results was 38 hours.
Testing patterns also reflected ordering practices. Just 34% of the patients underwent influenza, RSV, and SARS-CoV-2 testing prior to extended panel testing. In addition, most tests were ordered in patients discharged without a relevant respiratory diagnosis.
The findings showed that chest X-ray results were the most significant factor associated with antibiotic use, and admission to the intensive care unit was associated with increased intravenous antibiotic use.
The investigators noted limitations, including the study's retrospective design and reliance on documentation. They also stated that the results reflected a single institutional testing panel and may not be generalizable. Additionally, presumed time in isolation was an estimate and may not reflect actual time spent in isolation.
“Testing for respiratory viruses beyond influenza, SARS-CoV-2, and RSV was frequently performed at our institution; however, we failed to demonstrate an objective benefit in adult inpatients with regard to antibiotic usage or inpatient length of stay,” wrote lead study author Jake Fletcher, a medical student in the Department of Medicine at the Melbourne Medical School at the University of Melbourne as well as The Northern Hospital of Northern Health in Australia, and colleagues.
The researchers reported no conflicts of interest.
Source: Infectious Diseases
