Background:
We have developed two novel assays to detect herpes simplex virus types 1 and 2 (HSV-1/2) in various viral transport media and specimen matrices on the BD ProbeTec ET System.

Objective:
To evaluate analytical and clinical performance of the BD ProbeTec HSV-1/2 assays.

Method:
Transport medium containing the specimen was added directly to sample buffer, boiled for 5 minutes and assayed on the BD ProbeTec utilizing dried reagents. Analytical studies tested transport media with and without clinical matrix. The clinical evaluation tested 117 genital, oral, dermal, and ocular swabs in M4, M4-RT or M5 transport medium (Remel) for each assay against culture.

Result:
The analytical sensitivities of the assays for cloned plasmid DNA were 288 copies/reaction for HSV-1 and 118 copies/reaction for HSV-2. Both assays proved compatible with M4, M4-RT, M5 and UTM-RT (BD Diagnostics) transport media. The HSV-1 assay identified 24/117 and the HSV-2 assay identified 37/117 specimens as positive. Culture only identified 23 HSV-1 and 23 HSV-2 positives.

Conclusion:
The results presented here demonstrate the potential for the BD ProbeTec ET HSV-1/2 assays to replace conventional culture as a sensitive means for the detection of HSV.

Implications:
As has been reported elsewhere, a large number of additional positives were identified using the molecular method compared to conventional viral culture. A reasonable explanation is that the molecular method may be more sensitive than culture. Culture sensitivity may be reduced because of its dependence on recovering viable virus whereas the molecular method requires only the presence of intact DNA. The high number of positive results seen with the HSV-2 assay typifies the challenges associated with validation of a novel, more sensitive technology against an established gold standard. To determine true sensitivity and specificity of these assays, comparison to one or more alternative molecular methods will be required.