Rapid influenza A testing for novel H1N1: point-of-care performance

Abstract

Objectives: The 2009 outbreak of novel influenza A H1N1 reached a pandemic status on June 11, 2009. Early detection is a key factor for management and infection-control practices. Recent studies have suggested a difference in performance of rapid influenza kits for influenza A H1N1. Our goal was to evaluate the performance of the QuickVue influenza A+B test (Quidel Corp., San Diego, CA) in an emergency department setting and determine the most current epidemiologic trends in our community.

Methods: Results from 1137 samples for influenza A collected between April 8, 2009 and June 30, 2009 were retrospectively reviewed. Results of QuickVue influenza A+B test were compared with R-Mix viral culture and DFA results. Age distribution and hospitalization rates by age group were analyzed to further delineate the epidemiology of influenza A in a suburban hospital.

Results: The sensitivity of the rapid test was 77%, the specificity was 85%, the positive predictive value was 74%, and the negative predictive value was 87%. We found a similar age distribution for positive influenza tests and admissions when compared with the national Centers for Disease Control and Prevention data.

Conclusions: The QuickVue influenza A+B test is a sensitive assay for the novel H1N1 strain of influenza. In our hospital, the group with highest risk of hospital admission was patients aged < 25 years.