Discordant rapid HIV tests: lessons from a low-resource community

Area of Science:

• Infectious Diseases
• Public Health
• Diagnostic Testing

Background:

• HIV rapid antibody tests are essential for HIV screening in Africa.
• Discordant results between dual rapid tests can occur, raising questions about their implication for early HIV infection detection.
• Previous studies focused on high HIV prevalence populations, leaving a gap in understanding discordant test results in low prevalence settings.

Purpose of the Study:

• To investigate the occurrence and significance of discordant rapid HIV tests in a low-resource community.
• To determine if discordant rapid tests are indicative of early HIV infection in populations with low HIV prevalence.
• To assess the association between discordant rapid tests and indicators of acute HIV infection.

Main Methods:

• A cross-sectional study enrolled HIV status-unaware adults with recent exposure to unsafe sex, assessed using the UNC-Malawi Risk Screening Score.
• Participants underwent dual rapid HIV testing (Determine™ HIV 1/2 and Uni-Gold™ HIV) and plasma HIV-1 antigen testing (COBAS® Ampliprep/COBAS® Taqman® HIV-1 assay).
• Western blot was performed for individuals with detected HIV-1 antigen to confirm HIV status.

Main Results:

• Of 408 participants, 1.0% had established HIV infection.
• The prevalence of discordant rapid tests was 2.45% (sequential) and 2.94% (simultaneous).
• Discordant rapid tests were significantly associated with higher risk scores (OR 10.88) and detectable HIV-1 RNA (OR 26.06), indicating early HIV infection.

Conclusions:

• In low HIV prevalence populations, discordant rapid HIV tests in individuals with sexual risk behavior should strongly suggest early HIV infection when discordance rates are below 5%.
• These findings support heightened clinical suspicion for acute HIV when rapid tests yield conflicting results in at-risk individuals.
• The study highlights the importance of considering discordant rapid tests as a potential indicator of early HIV infection in diverse epidemiological settings.