Guideline addresses viral testing in patients with community-acquired pneumonia

An evidence-based clinical practice guideline on nucleic acid–based testing of respiratory samples for viral pathogens other than influenza in adults with suspected community-acquired pneumonia (CAP) was recently issued by the American Thoracic Society.

Increasing recognition of noninfluenza viral causes of CAP and expanded availability of diagnostic tests led to this update of a previous guideline, according to the new guidance, which was published in the May 1 American Journal of Respiratory and Critical Care Medicine.

The guideline panel made two recommendations:

• In outpatients with suspected CAP, physicians should not routinely use nucleic-acid based testing of respiratory samples for viral pathogens other than influenza (conditional recommendation, very low-quality evidence). There was limited evidence of altered antibiotic use with viral testing, the guideline stated, and little current evidence showing that the practice affects antibiotic management.
• In hospitalized patients with suspected CAP, physicians should use nucleic acid-based testing only in patients with severe CAP or in immunocompromised patients (including neutropenia, active cancer therapy, history of solid organ or blood component transplant, advanced HIV disease, or chronic use of immunosuppressive medications including systemic corticosteroids) (conditional recommendation, very low-quality evidence).

The highly sensitive and specific nucleic acid amplification tests allow improved detection of respiratory viruses, the guideline stated. Noninfluenza viruses are detected in a substantial proportion of severe CAP cases and have been associated with increased need for mechanical ventilation, need for prolonged intensive care support, and death, the authors noted.

They wrote, “On the basis of GRADE criteria, the quality of evidence on this topic was rated as being very low, with few studies assessing the effect of noninfluenza viral diagnoses on key patient-centered outcomes.”