Herpes simplex virus type 2 (HSV-2) IgG index values in two immunoassays in relation to HSV-2 IgG inhibition assay results

Diagn Microbiol Infect Dis. 2019 Nov;95(3):114864. doi: 10.1016/j.diagmicrobio.2019.07.002. Epub 2019 Jul 13.

Abstract

CDC guidelines recommend confirmatory testing of sera with low-positive indices (1.10-3.50) in the HerpeSelect® (HSLT) HSV-2 IgG screening assay. To determine if this recommendation is adequate for our patient population, we reviewed HSLT HSV-2 IgG screening indices for 262 screen-positive sera (index >1.10) tested in our confirmatory assay, which assesses inhibition of binding to recombinant gG2 by HSV-1- and HSV-2-infected cell lysates. To determine how the recommendation affects other screening assays, we tested these samples in the Liaison® HSV-2 IgG assay. Of 124 false-positive sera, 20% and 39% had an index >3.50 in the HSLT and Liaison screening assays, respectively. In both assays, 51% of 63 indeterminate sera (inhibition by HSV-1 lysate) had indices >3.50. Similarly, ≥75% of 75 true-positive samples exhibited indices >3.50 in both assays. Thus, confirmatory testing only of sera with low-positive HSV-2 IgG indices misses some false-positive and indeterminate samples, leading to misdiagnosis of HSV-2 infection.

Keywords: Confirmatory testing; Herpes simplex virus type 2; IgG Inhibition assay.

Publication types

  • Comparative Study

MeSH terms

  • Antibodies, Viral / blood
  • False Positive Reactions
  • Herpes Genitalis / diagnosis*
  • Herpesvirus 1, Human / immunology
  • Herpesvirus 2, Human / immunology
  • Herpesvirus 2, Human / isolation & purification*
  • Humans
  • Immunoassay / standards*
  • Immunoglobulin G / blood
  • Serologic Tests / standards*
  • Viral Envelope Proteins / immunology

Substances

  • Antibodies, Viral
  • Immunoglobulin G
  • Viral Envelope Proteins