Detecting DNA viruses in oral fluids: evaluation of collection and storage methods

• Formal independent evaluation of the DNA Genotek P-021 kit (prototype to the OM-501 kit).
• Viral loads remained constant for 6–9 months, yielding high quantities of DNA.
• After 14 months, DNA is highly degraded in frozen saliva but not in the P-021.
• DNA extraction from P-021 should be via commercial spin columns.
• The P-021 is ideal for collection, long-term storage, and detection of viral DNA.

Storing saliva for nucleic acid diagnostics is problematic in resource-constrained settings. DNA Genotek's OMNIgene™ · DISCOVER kit aims to stabilise microbial DNA at room temperature. We evaluate this for long-term storage, determining DNA quantity/purity and human herpesvirus 8 (HHV-8) load as indicator. Viral loads and DNA degradation were assayed over 14 months in HHV-8–negative saliva spiked with cell-associated and cell-free virus and saliva collected fresh frozen and into kits from 10 HIV-positive patients. Viral loads remained constant for 6–9 months, yielding high quantities of DNA: subsequent losses were ≤48%. Patient samples, frozen or kit stored, produced pure DNA of comparable concentration. Higher HHV-8 detection in frozen saliva resulted from losses during ethanol precipitation using kits. After 14 months, DNA degradation was significant in frozen saliva, but that in kits had integrity similar to fresh samples. Storing frozen saliva is detrimental. This kit is well suited for collection, long-term storage, and assay of viral DNA in resource-constrained settings.