Journal of Clinical Microbiology, April 2007, p. 1081-1086, Vol. 45, No. 4
0095-1137/07/$08.00+0 doi:10.1128/JCM.01718-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Emory University School of Medicine, Atlanta, Georgia,1 Children's Medical Center and the University of Texas Southwestern Medical Center, Dallas, Texas,2 Centers for Disease Control and Prevention, Atlanta, Georgia,3 The Children's Hospital, Denver, Colorado,4 Cepheid, Sunnyvale, California5
Received 18 August 2006/ Returned for modification 6 October 2006/ Accepted 12 January 2007
The GeneXpert Dx system (Cepheid, Sunnyvale, CA) is a fully integrated and automated nucleic acid sample preparation, amplification, and real-time detection system. It consists of an instrument, a personal computer, and disposable fluidic cartridges. The analytical sensitivity and specificity of the GeneXpert enterovirus assay (GXEA) were determined with a panel of 63 different enterovirus serotypes and 24 other microorganisms, respectively. The potential for blood, hemoglobin, white blood cells, and excess protein to interfere with the assay was also assessed. The performance parameters of the GXEA were determined at three sites with 102 cerebrospinal fluid (CSF) samples obtained from patients with suspected meningitis. All samples were tested for enterovirus RNA with locally developed reverse transcription-PCR (RT-PCR) assays at the trial sites and with a seminested RT-PCR and an analyte-specific reagent (Cepheid) at a reference laboratory. The 5' nontranslated region was the target for all of the PCR assays except the seminested RT-PCR, which amplified a VP1 sequence. The VP1 amplicon was sequenced to identify the enterovirus types. Consensus reference laboratory RT-PCR results were used to classify cases of enteroviral meningitis. The GXEA detected all of the enterovirus serotypes and none of the other microorganisms tested except rhinovirus 16. The assay was unaffected by moderate amounts of blood or blood components. Thirty-six (35%) of the CSF samples tested had at least one positive PCR result. Eleven different enterovirus serotypes were identified in the positive samples. The GXEA had a sensitivity of 97.1% (95% confidence interval [CI], 84.7 to 99.9%) and a specificity of 100% (95% CI, 94.6 to 100%) for the diagnosis of enteroviral meningitis.
Published ahead of print on 24 January 2007.
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