Performance of the focus and Kalon enzyme-linked immunosorbent assays for antibodies to herpes simplex virus type 2 glycoprotein G in culture-documented cases of genital herpes

Abstract

Glycoprotein G-based herpes simplex virus type 2 (HSV-2) enzyme-linked immunosorbent assays from Focus and Kalon were performed with specimens from 118 patients with culture-documented genital herpes episodes, and their results were compared. Sensitivity was 52% by Kalon and 86% by Focus for first HSV-2 episodes and 100% (for each of the two tests) for recurrent HSV-2. Median times to seroconversion were 120 days by the Kalon assay, 21 days by the Focus assay, and 68 days by Western blotting assay. Values for specificity were 100% (Kalon) and 93% (Focus).

FIG. 1.

Time to seroconversion following onset of genital infection in HSV-1-seronegative, HSV-2-seronegative patients (primary episode). Note that censored data (the day from onset that a subject remained seronegative when he/she left the study) affect the curves. Thus, seven subjects failed to seroconvert by Kalon at their latest serum postonset (days 66 to 136) and were dropped from further consideration. Of the remaining subjects, the final one seroconverted by Kalon at day 168. Only one subject who was still eligible failed to seroconvert by day 117 by Focus and was censored at the point where the curve is truncated.

FIG. 2.

Time to seroconversion following onset of genital HSV-2 infection in HSV-1-seropositive, HSV-2-seronegative patients (nonprimary episode). Note that these survival curves include censored data (when the latest serum available remained seronegative). For example, samples from eight subjects drawn 58 to 139 days postonset were negative by Kalon and were, therefore, censored from further analyses. At day 193 the sixth eligible subject seroconverted by Kalon. Day 139 was the last day for which subjects were neither eligible nor seropositive by Focus or WB.