Reliable detection and quantitation of viral nucleic acids in oral fluid: Liquid phase-based sample collection in conjunction with automated and standardized molecular assays

Oral fluid has been used widely as sample matrix for the detection and quantitation of viral nucleic acids. However, in the vast majority of previous studies, various methods for collection of oral fluid and molecular assays lacking automation and standardization were used. In this study, a new standardized liquid phase-based saliva collection system was employed followed by a fully automated viral nucleic acid extraction and real-time PCR using commercially available in vitro diagnostics (IVD)/Conformité Européene (CE) labeled molecular assays. When the lower limit of detection of herpes simplex virus (HSV)-1/2 DNA, varicella zoster virus (VZV) DNA, and hepatitis C virus (HCV) RNA in spiked oral fluid was tested, the results were found to be comparable to those with defined sample materials recommended by the assay manufacturers. When clinical specimens were investigated, 21 of 25 (84%) oral fluids obtained from patients with clinically apparent herpetic lesions tested positive for HSV DNA, 7 of 10 (70%) oral fluids obtained from patients with Ramsay Hunt Syndrome tested positive for VZV DNA, and 19 of 40 (48%) oral fluids collected from patients with chronic HCV infection tested positive for HCV RNA. The automated extraction instruments completed all extractions without malfunction and no inhibitions were observed throughout the entire study. Liquid phase-based saliva collection in conjunction with automated and standardized commercially available molecular assays allows reliable quantitation of viral nucleic acids in oral fluid samples and may contribute to improved comparable and interpretable test results.