Performance of the GeneXpert enterovirus assay for detection of enteroviral RNA in cerebrospinal fluid.
BACKGROUND
The GeneXpert Dx System allows for automated extraction, processing, amplification and real-time detection of target nucleic acids.


OBJECTIVE
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.


METHODS
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.
Marlowe
Elizabeth M
EM
SCPMG Regional Reference Laboratories, 11668 Sherman Way, North Hollywood, CA 91605, United States. Elizabeth.m.marlowe@kp.org
Novak
Susan M
SM
Dunn
James J
JJ
Smith
Amy
A
Cumpio
Joven
J
Makalintal
Edna
E
Barnes
Darryl
D
Burchette
Raoul J
RJ
D004770:Enterovirus / Q000235:genetics / Q000302:isolation & purification*; D004769:Enterovirus Infections / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D012367:RNA, Viral / Q000134:cerebrospinal fluid*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D021161:Self-Sustained Sequence Replication / Q000379:methods; D012680:Sensitivity and Specificity
D012367:RNA, Viral