A rapid and simple isothermal nucleic acid amplification test for detection of herpes simplex virus types 1 and 2

Abstract

Background A simple and rapid IsoAmp ® HSV assay has been developed for qualitative detection of herpes simplex virus (HSV) types 1 and 2 from genital lesions. Sample preparation involved a simple dilution step and the diluted specimens were directly added to the device and amplified by isothermal helicase-dependent amplification (HDA). Amplification products were then detected by a DNA strip embedded in a disposable cassette without any instrument. The total test turn-around time is less than 1.5 h from specimen processing to result reporting. Objectives To evaluate the analytical and clinical performance of the IsoAmp ® HSV assay as well as the robustness and reproducibility of the assay. Study design The analytical sensitivity of the IsoAmp ® HSV assay was determined using both HSV-1 and HSV-2. Clinical performance was evaluated using 135 frozen specimens collected from patients with suspected HSV infection in genital area. Results The analytical sensitivity of the assays was 5.5 and 34.1 copies/reaction for HSV-1 and HSV-2 respectively with a 95% confidence interval. When the herpes viral culture was used as the reference standard, the clinical sensitivity and specificity of the IsoAmp ® HSV assay were 100.0% and 96.3% respectively. The inter-laboratory reproducibility achieved an overall 97.5% agreement by testing a total of 80 blinded HSV-1 samples among five laboratories. Conclusion Adequate analytical and clinical performance of the IsoAmp ® HSV assay was demonstrated. This assay is simple to perform and has acceptable inter-laboratory reproducibility.