Herpes simplex virus type 2 (HSV-2) Western blot confirmatory testing among men testing positive for HSV-2 using the focus enzyme-linked immunosorbent assay in a sexually transmitted disease clinic.
OBJECTIVE
The objective of this study was to define the positive predictive value (PPV) of the Focus herpes simplex virus type 2 (HSV-2) enzyme-linked immunosorbent assay (ELISA) in a low HSV-2 prevalence population and to develop a new test interpretation algorithm.


METHODS
HSV-2 Western blots were performed on sera from male sexually transmitted disease clinic patients testing HSV-2 ELISA-positive and used to define a new class of indeterminate HSV-2 ELISA result. HSV-2 Western blots were then prospectively performed on sequential sera with indeterminate HSV-2 ELISAs.


RESULTS
Ninety-one (84%) of 108 HSV-2 ELISA-positive sera tested HSV-2 Western blot-positive. Western blot positivity was more common in men without herpes simplex virus type 1 (HSV-1) antibody than in those with HSV-1 antibody (93% vs 76%, P = 0.02) and in men with a history or clinical evidence of genital lesions (88% vs 80%, P = 0.30). Selectively raising the ELISA index value defining HSV-2 positivity from >1.1 to >or=3.0 either among HSV-1-positive men or among those without a history or clinical evidence of genital lesions increased the PPV to >or=93%. Prospective evaluation of an algorithm incorporating HSV-1 serostatus found that 11 of 70 persons with indeterminate HSV-2 ELISAs were Western blot-positive.


CONCLUSIONS
Clinicians should consider selectively using a higher index value to define Focus ELISA HSV-2 positivity based on either HSV-1 serostatus or clinical circumstances.
Golden
Matthew R
MR
Department of Medicine, University of Washington, Seattle, USA. golden@u.washington.edu
Ashley-Morrow
Rhoda
R
Swenson
Paul
P
Hogrefe
Wayne R
WR
Handsfield
H Hunter
HH
Wald
Anna
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D000554:Ambulatory Care Facilities; D000914:Antibodies, Viral / Q000097:blood*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D006558:Herpes Genitalis / Q000175:diagnosis* / Q000453:epidemiology*; D018258:Herpesvirus 2, Human / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D012680:Sensitivity and Specificity; D012749:Sexually Transmitted Diseases / Q000517:prevention & control
D000914:Antibodies, Viral