Performance of herpes simplex challenges in proficiency testing: observations from the College of American...

Herpes simplex virus (HSV) is a common sexually transmitted disease that is decreasing in prevalence. Herpes simplex virus challenge cases have performed well in the educational College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology. However, since gynecologic cytology proficiency testing (PT) was instituted, performance of HSV challenge cases has worsened.

To determine if the decrease in performance for HSV challenges is due to inexperience in identifying herpes virus or "gaming" of PT.

We compare graded (field-validated) and ungraded (educational) slides with HSV prior to PT (1991- 2005) and after PT (2006 and 2007) in an attempt to characterize changes in performance of slides demonstrating purely HSV cellular features. All HSV slides were negative for intraepithelial lesion with the specific reference interpretation of HSV. Slides were excluded from analysis if they demonstrated more than one diagnostic category or had squamous intraepithelial lesion in addition to HSV changes.

A total of 40 634 HSV responses were evaluated. A significant difference existed in the diagnosis of HSV in PT compared with graded challenges prior to PT (96.6 versus 98.6; P < .001). No difference was seen in educational challenges pre-PT and post-PT (P = .14). No difference was present between slide preparation type; however, a difference was seen between cytotechnologist and pathologist response.

There is a change in the performance of slide challenges demonstrating the cellular features of HSV in PT, most likely due to testing strategies of participants, rather than lack of recognition of HSV secondary to decreased prevalence.