Rapid Testing Algorithm Performance in a Low-Prevalence Environment

Eugene G. Martin, Julia Cornett, Debbie Y. Mohammed, Gratian Salaru

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: The performance of a statewide HIV rapid test algorithm (RTA) in a low-prevalence setting (0.71%) was examined for 3 years. METHODS: An initial rapid screening by HIV-1/2 Ag/Ab Combo test (RT#1) with Ab verification using a second, different rapid test (RT#2) was conducted. Clinic referral was immediate for antigen-only-positive screens. Antibody-positive screens were confirmed by RT#2. Specimens were collected following discordant RTA results (initially Ab-POS by RT#1, but negative on RT#2) and tested in accordance with the current Centers for Disease Control and Prevention/Association of Public Health Laboratories-based HIV diagnostic algorithm supplemented by a quantitative viral load whenever possible. RESULTS: Of 310,785 tests performed, 2400 preliminary positive screens were identified; 2191 (91.8%) confirmed by RT#2. Of 13 Determine Combo AG-POS results identified, only 1 confirmed positive. Of the remaining 196 discordant results, 182 (92.9%) were uninfected, including 13 with AG-POS/AB-POS results. Of 14 true positives (7.1%) identified after discordant RTA results, the average quantitative HIV-1 viral load was 277,385 copies/mL, but 5 (35.7%) of 14 had viral loads <1000 copies/mL. Among the 2191 "presumptive positive" by RTA, 3 false-positive (FP) RTAs were reported (both rapid tests having positive results, while the HIV-1/2 Ag/Ab assay and quantitative HIV-1 viral load showed negative results). CONCLUSIONS: The RTA was effective in predicting true-positive HIV test results and facilitating linkage to care. Discordant results were infrequent. Fingerstick DC Ag detection identified a single early infection. Many discordant cases that were subsequently positive were associated with viral loads <1000 copies/mL.

Original languageEnglish (US)
Pages (from-to)S35-S40
JournalSexually transmitted diseases
Volume47
Issue number5S Suppl 1
DOIs
StatePublished - May 1 2020

All Science Journal Classification (ASJC) codes

  • Dermatology
  • Public Health, Environmental and Occupational Health
  • Microbiology (medical)
  • Infectious Diseases

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