Table 3.

Narrative Summary of Studies Including Patients with a Variety of Respiratory Illnesses; Comparison Group: Positive PCR versus Negative PCR Viral Results

Author, Year (Reference)	Study Design	Setting/Participants	Key Results
Kim et al., 2018 (38)	Retrospective cohort study of multiplex PCR testing for viral pathogens, performed when severe pneumonia did not respond to empirical antibiotics, when imaging revealed ground-glass opacities suggestive of atypical pathogens, or when patients were immunocompromised	515 adult patients admitted to the medical ICU with severe pneumonia, including CAP, HCAP, or HAP; of 69 patients with positive PCR results, 24 received a diagnosis of CAP (34.8%)	Of the 515 patients who underwent testing for viral pathogens, 69 (13.4%) had a positive result. Detection of a viral pathogen led to changes in the disease management in 23 (33.3%) patients, including addition of antiviral therapy in 12 patients and discontinuation of antibiotics in 2 patients. Outcomes for patients with management changes were compared with those without management changes, with no significant difference seen in hospital or ICU LOS or in-hospital mortality.
Mayer et al., 2017 (37)	Retrospective cohort study of patients in whom a multiplex PCR for respiratory viruses was performed	Pediatric (n = 72) and adult (n = 182) in- and outpatients with upper or lower RTI; among adults, 35.7% had a diagnosis of CAP	Excluding patients who received antibiotics for other indications, antibiotic treatment was stopped in 2 of 35 adults (5.7%) in whom a viral pathogen was detected by using PCR. In adults with a positive viral PCR result, management was judged to be correct in 34% (12 of 35) after PCR results became available.
Yee et al., 2016 (36)	Retrospective cohort study comparing patients with a positive multiplex viral PCR result to patients with a negative test result	186 adults in a hospital setting (either ED or inpatient) with suspected ILI; 19.9% (37 of 186) of patients had suspected pneumonia	Among hospitalized patients, empiric oseltamivir was discontinued in 66.7% (10 of 15) of patients with a negative viral test result and in 100% (4 of 4) of patients who tested positive for a virus other than influenza. Empiric antibiotics were discontinued in 14.6% (6 of 41) of patients with a negative viral PCR result and in 26.3% (5 of 19) of patients with a positive viral PCR result.

Definition of abbreviations: CAP = community-acquired pneumonia; ED = emergency department; HAP = hospital-acquired pneumonia; HCAP = health care–associated pneumonia; ILI = influenza-like illness; LOS = length of stay; RTI = respiratory tract infection.