New guidance on testing for noninfluenza viral pathogens in community-acquired pneumonia

The American Thoracic Society issued a new clinical practice guideline that addresses the use of nucleic acid-based testing for noninfluenza viral pathogens in community-acquired pneumonia in the outpatient and inpatient setting.

“Given the important etiologic contributions to community-acquired pneumonia of noninfluenza respiratory viruses and the expanding commercial availability of multiplex testing for these viruses, the ATS commissioned the current document to provide an evidence-based clinical practice guideline regarding the pertinence of nucleic acid-based testing of respiratory samples for noninfluenza respiratory viruses in adults with suspected community-acquired pneumonia,” the authors wrote in the American Journal of Respiratory and Critical Care Medicine.

To assess the diagnostic utility of nucleic acid-based testing of respiratory samples for noninfluenza viral pathogens among individuals with community-acquired pneumonia (CAP), an ATS multidisciplinary panel conducted a pragmatic systemic review and applied Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. These standards determined the designation of the quality of evidence as high, moderate, low or very low.

The panel evaluated studies that compared positive viral tests with negative viral tests and those that evaluated tests that involved viral and bacterial assays.

CAP is caused by a wide range of respiratory pathogens, prominently including viruses. However, the only viral pathogen addressed in the 2019 clinical practice guideline was influenza. The panel determined that, given increasing recognition of noninfluenza viral causes of CAP and expanded availability of diagnostic tests among clinicians, it was necessary to update the previous recommendations to help guide treatment, according to a press release issued by the ATS.

In outpatients with suspected CAP, routine nucleic acid-based testing of respiratory samples for viral pathogens other than influenza is not recommended, according to the new guideline.

In patients who are hospitalized with suspected CAP,  nucleic acid-based testing of respiratory samples for viral pathogens other than influenza only is recommended for those with severe CAP or those who are immunocompromised, including patients with neutropenia, active cancer therapy, history of solid organ or blood component transplant, advanced HIV or chronic use of immunosuppressive medications, according to the new guideline.

Current evidence does not support a clinically significant relationship between testing for noninfluenza viral pathogens and antimicrobial treatment, and available evidence is of low quality due to methodological issues, including bias risk and imprecision, according to the authors.

“Molecular diagnostics for lung infections are rapidly evolving. We will continue to monitor developments to determine when additional updates are appropriate,” ATS Assembly on Pulmonary Infection and Tuberculosis subcommittee co-chairs Scott E. Evans, MD, professor in the department of pulmonary medicine at The University of Texas MD Anderson Cancer Center and Charles S. Dela Cruz, MD, PhD, associate professor of medicine and of microbial pathogenesis and director of the Center for Pulmonary Infection Research and Treatment at Yale Medicine, said in the release. “We also look forward to reviewing more literature that directly link the use of molecular diagnostics on important outcomes, such as death, morbidity, antimicrobial drug use patterns and costs.”