Variable performance of HSV-2 IgG assays highlights the importance of western blot confirmation in a low-prevalence population

Herpes simplex virus type 2 (HSV-2) is a highly prevalent sexually transmitted infection, underscoring the importance of accurate serodiagnosis. While enzyme-linked immunosorbent assays (ELISAs) are commonly used clinically, their diagnostic performance compared to gold standard western blot (WB) remains uncertain. To compare the diagnostic accuracy of two ELISA-based assays, HerpeSelect 2 and NovaLisa, with the Euroimmun HSV-2 WB assay for the detection of HSV-2-specific IgG antibodies. Four hundred serum samples from adult males residing in Qatar were analyzed. Diagnostic metrics including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overall accuracy, and Cohen’s kappa coefficient were calculated for each ELISA assay relative to the Euroimmun HSV-2 WB assay. HerpeSelect had a sensitivity of 78.8%, specificity of 78.3%, PPV of 25.7%, NPV of 97.5%, and fair agreement with WB (Cohen’s kappa = 0.296). NovaLisa performed less well, with a sensitivity of 69.7%, specificity of 66.9%, PPV of 18.3%, NPV of 95.4%, and poor agreement with WB (Cohen’s kappa = 0.162). Both assays significantly overestimated HSV-2 seropositivity compared with WB (HerpeSelect: 26.8%, NovaLisa: 33.5%, WB: 8.3%). A high proportion of false positives was observed for both ELISA assays. Although HerpeSelect demonstrated stronger agreement with the Euroimmun HSV-2 WB reference assay compared with NovaLisa, both ELISA-based assays exhibited low PPVs and high false-positive rates in this low prevalence population. These findings support the need for confirmatory testing or the adoption of automated chemiluminescent immunoassay platforms to enhance diagnostic accuracy for HSV-2.