Conference Coverage

Faster multiplex PCR improved management of pediatric acute respiratory illness


Key clinical point: Faster multiplex PCR respiratory panel results helped guide management of young children hospitalized with acute respiratory illness.

Major finding: Empiric antibiotic therapy, thoracic radiography, and median length of stay all decreased.

Data source: A descriptive single-center retrospective study of 2,905 children up to 24 months old who were hospitalized with acute respiratory illness and tested positive for at least one virus on a multiplex PCR.

Disclosures: Dr. Selvarangan disclosed grant support from both Biofire Diagnostics and Luminex corporation, and an advisory relationship with BioFire.



– Switching to a faster, more comprehensive multiplex PCR viral respiratory assay enabled a hospital to discharge young children with acute respiratory illnesses sooner, prescribe oseltamivir more often, and curtail the use of antibiotics and thoracic radiography, Rangaraj Selvarangan, PhD, reported at an annual meeting on infectious disease.

Amy Karon

Dr. Rangaraj Selvarangan

Acute respiratory illness is a leading reason for pediatric hospitalization, is usually viral in nature, and continues to fuel the overuse of antibiotics. Multiplex PCR respiratory panel assays have been available in the United States for about a decade, but uptake has varied. “As one of the early adopters of the technology, we wanted to see how it might affect patient care,” Dr. Selvarangan said.

For the study, the researchers compared hospital records from December 2008 through May 2012, when Children’s Mercy hospital used the Luminex xTAG Respiratory Viral Panel, with records from August 2012 through June 2015, after the hospital had switched over to the Biofire FilmArray Respiratory Panel. FilmArray targets the same 17 viral pathogens as the Luminex panel, but also targets Bordetella pertussis, Chlamydia pneumoniae, and Mycoplasma pneumoniae, seasonal influenza A, parainfluenza type 4, and four coronaviruses.

The study included children aged up to 2 years who were not on immunosuppressive medications, in the NICU, or hospitalized for more than 7 days. For this population, the two panels yielded similar rates of positivity overall (about 60%) and for individual viruses, Dr. Selvarangan said. A total of 810 patients tested positive for at least one virus on the Luminex panel, and 2,096 patients tested positive on FilmArray. Results for FilmArray were available within a median of 4 hours, versus 29 hours for Luminex (P less than .001). The prevalence of empiric antibiotic therapy was 44% during the Luminex era and 28% after the hospital switched to FilmArray (P less than .001). Rates of antibiotic discontinuation rose from 16% with Luminex to 23% with FilmArray (P less than .01). Strikingly, oseltamivir prescriptions rose five-fold (from 17% to 85%; P less than .001) after the hospital began using FilmArray, which covers seasonal influenza. Finally, use of chest radiography fell significantly in both infants and older children after the hospital began using FilmArray instead of Luminex.

Clinicians might have become more comfortable interpreting molecular test results over time, which could have altered their clinical decision-making and thereby biased the study results, Dr. Selvarangan noted. Although at least four other single-center retrospective studies have linked multiplex PCR assays to better antibiotic stewardship, this study is one of the first to directly compare clinical outcomes between two assays, he added. More studies are needed to help guide choice of multiplex assays, whose cost remains a major barrier to widespread use, he concluded.

Dr. Selvarangan disclosed grant support from both Biofire Diagnostics and Luminex corporation, and an advisory relationship with BioFire.

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