Performance of the GeneXpert enterovirus assay for detection of enteroviral RNA in cerebrospinal fluid.

ABSTRACT

BACKGROUND: The GeneXpert Dx System allows for automated extraction, processing, amplification and real-time detection of target nucleic acids. OBJECTIVES: To evaluate the performance of the Cepheid Xpert enterovirus (EV) assay for detection of EV RNA compared to a nucleic acid sequence based amplification (NASBA) assay and a user-developed TaqMan RT-PCR assay. STUDY DESIGN: Assays were evaluated using a 12-member proficiency panel and up to 138 CSF specimens. Samples in which EV RNA was detected by two or more assays were considered true positives. RESULTS: The GeneXpert, NASBA, and TaqMan assays correctly identified 10, 8, and 7 of 12 proficiency panel members, respectively. For detection of EV RNA in CSF, the sensitivities of the GeneXpert, NASBA, and TaqMan were 100%, 87.5%, and 96%, respectively. There were no false positives. Two samples tested by GeneXpert and NASBA yielded indeterminate or invalid results and could not be resolved. CONCLUSIONS: The Xpert EV assay is a sensitive and specific method for detection of EV RNA in CSF specimens. The ease of use, random access capability, and minimal hands-on time with the automated GeneXpert system affords laboratories with little molecular diagnostics expertise an opportunity to complete a clinically useful testing within 2.5 h.