High percentage of false-positive results for influenza B obtained with a rapid influenza point-of-care test.

The monthly mean percent positivites for B were 27%, 26%, 29%, and 49% for September, October, November, and December 2013, respectively. We observed 55% positivity for B in January 2014 and 58% for the first 2 weeks of February. Because these percentages were much greater than the national average of <4% [2], we compared the results obtained with the POCT to those obtained with the eSensor respiratory viral panel (RVP; GenMarkDx, Carlsbad, CA). This test distinguishes influenza A subtypes, including the 2009 pandemic H1N1 (pH1N1), from nonpandemic H1N1 and H3N2, as well as influenza B and several other common respiratory viruses. When the POCT yielded a positive result for influenza A or B, a second specimen was immediately obtained and analyzed using the RVP. We compared 43 POCT A/RVP paired specimens and 66 POCTB/RVPpaired specimens (Figure 1). For influenza A, 93% of those samples were identified as pH1N1 by our RVP. Seven percent were negative for any