Department of Medicine

IU Infectious Diseases Laboratory

Detection of Herpes Simplex Virus (HSV) 1 and 2
by Nucleic Acid Amplification

The Becton Dickinson (BD) Qx HSV1/2 assay uses strand displacement technology to detect Herpes Simplex virus 1 and 2. Nucleic acid is extracted from each sample using high pH, with the liberated DNA being bound to metal beads, washed, and eluted for amplification.  The DNA is transferred to a priming microwell, which contains the amplification primers, and fluorescently labeled detector probes. After incubation, the mixture is transferred to the amplification microwell, which contains DNA polymerase and a restriction endonuclease, necessary components of the strand displacement assay.  The amplification wells are incubated in a thermally controlled fluorescent reader, with the presence or absence of HSV 1 or 2 determined by calculating the peak fluorescence over the course of the amplification and by comparison to a predetermined threshold value. An extraction control (EC) is incorporated into each reaction to confirm that proper extraction has occurred.  This process is completely automated by using the Viper instrument in extracted mode.  The performance characteristics of this assay were established by our laboratory for anogenital lesions collected from symptomatic individuals, and placed into either a universal viral transport medium or into the Qx lesion diluent tube. All other sample types are unacceptable. The limit of detection for this assay is 85 virions per ml for HSV 1 and 635 virions per ml for HSV 2.