A Comparison of the Nanosphere (Northbrook, IL) Verigene Respiratory Virus Plus Nucleic Acid Test (RV+) With a Traditional Testing Algorithm for Influenza A/B and RSV

Abstract

Influenza and RSV infections result in 200,000 and 100,000 hospitalizations annually in the United States, respectively. Prompt and accurate diagnosis of these viruses is crucial to the treatment and cohorting of hospitalized patients. Our traditional testing algorithm consists of rapid membrane-based EIA test, respiratory virus DFA panel, and respiratory virus culture. Our PCR-based algorithm, the RV+, is a qualitative nucleic acid multiplex test that detects influenza A (subtyped into 2009 H1N1, H1, or H3), influenza B, RSV A, and RSV B in nasopharyngeal swab specimens of symptomatic patients. The comparator was the combined result from the 3 traditional modalities, with any 1 positive counted as "detected." The overall sensitivity and revised specificity were 98% and 94%, respectively. RSV A sensitivity and revised specificity were 100% and 94%, respectively (26 samples, 3 falsepositives, 2 reclassified on discrepant analysis), and RSV B sensitivity and specificity were 100% (19 specimens). For interlaboratory comparison, the percentage of concordance (28 specimens) was 100% for influenza A 2009 H1N1 (8/8), influenza A H3 (7/7), and RSV B (3/3) and 90% for influenza B (9/10), The RV+ assay has an expected higher sensitivity than our comparator; therefore, we would expect "false"-positives giving an erroneously low specificity. Discrepant analysis performed using another PCR-based assay showed our positive call for RSV A was correct in 2 of the 3 false-positives. Traditional testing algorithms for respiratory virus detection are insensitive and labor-intensive. Turnaround time for a confirmed result can take days. Results from different assays can be contradictory, creating confusion. The RV+ yields a highly sensitive result in approximately 2.5 hours that requires no confirmation. From an economic perspective, if all areas of testing (labor, multiple methods, and reimbursement) are taken into account, the cost difference between the Verigene and a traditional algorithm is negligible.