Evaluation of the Xpert Flu for the Detection of Influenza A Virus and Influenza A/H1N1/2009 Strain

Abstract

Background: Xpert Flu (Cepheid, USA) allows for fully automated real-time RT-PCR using a single-use disposable cartridge. The aim of this study was to evaluate Xpert Flu for the detection of influenza A virus and subtype A/H1N1/2009 pandemic virus. Methods: We conducted a prospective comparison study for Xpert Flu with the RealTime ready Influenza A/H1N1 Detection Set (Roche Diagnostics, Germany). Analytical specificities of the assays were determined by testing commonly encountered respiratory viral pathogens, including parainfluenza virus type 1/2/3, rhinovirus A, rhinovirus B, metapneumovirus, adenovirus, and coronavirus. The analytical sensitivities and workflow of both methods were also assessed. Results: A total of 102 consecutive clinical specimens were tested by both methods. Total agreement between the two methods was estimated to be 99.0% (101/102): 11 A/H1N1/2009 and 3 seasonal influenza A by the RealTime ready Influenza A/H1N1 Detection Set; 10 and 3 by Xpert Flu. No cross-reactivity was observed between influenza A/H1N1/2009 and other respiratory viral pathogens in either method. The limits of detection of the RealTime ready Influenza A/ H1N1 Detection Set and Xpert Flu were 500 TCID50/ mL and 20 TCID50/mL, respectively. Xpert Flu required 85 minutes (10 minutes of hands-on time) for processing, while RealTime ready Influenza A/ H1N1 Detection Set took 128 minutes (30 minutes of handson time). Conclusion: The results of Xpert Flu were comparable to those of the RealTime ready Influenza A/H1N1 Detection Set. It is of note that the fully automated and closed system of Xpert Flu could be advantageous for reducing hands-on time and for preventing cross-contamination during the testing process. (Ann Clin Microbiol 2013;16:140-144)