Performance of rapid influenza diagnostic tests (QuickVue) for Influenza A and B Infection in India.

ABSTRACT

Background: Rapid point-of-care (POC) tests provide an economical alternative for rapid diagnosis and treatment of infl uenza, especially in public health emergency situations. Objectives: To test the performance of a rapid infl uenza diagnostic test, QuickVue (Quidel) as a POC test against a real-time polymerase chain reaction (RT-PCR) assay for detection of infl uenza A and B in a developing country setting. Study Design: In a prospective observational design, 600 patients with infl uenza-like illness (ILI) or with severe acute respiratory illness (SARI) who were referred to the Infl uenza Clinic of a tertiary care hospital in Srinagar, India from September 2012 to April 2013, were enrolled for diagnostic testing for infl uenza using QuickVue or RT-PCR. All infl uenza A-positive patients by RT-PCR were further subtyped using primers and probes for A/H1pdm09 and A/H3. Results: Of the 600 patients, 186 tested positive for infl uenza A or B by RT-PCR (90 A/ H1N1pdm09, 7 A/H3 and 89 infl uenza B), whereas only 43 tested positive for infl uenza (infl uenza A = 22 and infl uenza B = 21) by QuickVue. Thus, the sensitivity of the QuickVue was only 23% (95% confi dence interval, CI 17.3-29.8) and specifi city was 100% (95% CI 99.1-100) with a positive predictive value (PPV) of 100% (95% CI 91.8-100) and a negative predictive value (NPV) of 74.3% (95% CI 70.5-77.9) as compared to RT-PCR. Conclusions: The high specifi city of QuickVue suggest that this POC test can be a useful tool for patient management or triaging during a public health crisis but a low sensitivity suggests that a negative test result need to be further tested using RT-PCR.