title: Improved classification of recent HIV-1 infection by employing a two-stage sensitive/less-sensitive test strategy.
abstract: Current serologic techniques for the classification of recent HIV-1 infection produce some misclassifications, and, together with the loss to follow-up of individuals, results in decreased enrollment of HIV-infected persons into appropriate intervention programs. We report on the development of a sensitive/less sensitive (S/LS) test strategy that includes a rapid assay to quickly identify persons most likely to have recent infection, followed by an enzyme immunoassay (EIA) with exquisite specificity. The Uni-Gold Recombigen HIV rapid assay (UG; Trinity Biotech, Dublin, Ireland) was procedurally-modified and calibrated as an LS test to differentiate recent (<133 days) from established HIV infections using 178 samples from persons with known dates of infection. This method correctly classified 83.0% of recent infections, but with a high misclassification rate of persons with established infection. By performing the rapid test followed by a modified S/LS EIA, the positive predictive value of the combined results for recent infections was increased to 100%. This two-stage testing algorithm can result in an increased efficiency for the enrollment of recent infection cases over a standard EIA S/LS method alone due to provisional enrollment during an initial testing visit, and because of an increased accuracy for identifying truly recent infections. We conclude that the rapid S/LS assay provides a tool for capturing recent infection cases quickly and is particularly valuable in resource-limited settings, and that the two-stage strategy provides a more accurate identification of persons with recent HIV infection.
authors.affiliation: Department of Pathology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA. constant@umbi.umd.edu
authors.forename: Niel T
authors.initials: NT
authors.lastname: Constantine
authors.forename: Anne M
authors.initials: AM
authors.lastname: Sill
authors.forename: Noreen
authors.initials: N
authors.lastname: Jack
authors.forename: Kristen
authors.initials: K
authors.lastname: Kreisel
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Edwards
authors.forename: Thomas
authors.initials: T
authors.lastname: Cafarella
authors.forename: Harry
authors.initials: H
authors.lastname: Smith
authors.forename: Courtenay
authors.initials: C
authors.lastname: Bartholomew
authors.forename: Farley R
authors.initials: FR
authors.lastname: Cleghorn
authors.forename: William A
authors.initials: WA
authors.lastname: Blattner
mesh_terms: D000465:Algorithms; D002138:Calibration; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D015658:HIV Infections / Q000145:classification* / Q000175:diagnosis*; D006679:HIV Seropositivity / Q000175:diagnosis*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D012680:Sensitivity and Specificity; D013997:Time Factors