Evaluation of the HIV-1 Rapid Recency Assay and Limiting Antigen Avidity Enzyme Immunoassay for HIV Infection Status Interpretation in Long-Term Diagnosed Individuals in Thailand

<b>Background/Objectives:</b> Accurate surveillance of recent HIV infections is crucial for effective epidemic control and timely intervention. The Limited Antigen Avidity Enzyme Immunoassay (LAg-EIA) allows precise differentiation between recent and long-term HIV infections. To enhance accessibility, it has been developted into a point-of-care test, the Asanté™ HIV-1 Rapid Recency^® Assay (ARRA), a rapid immunoassay. This study evaluated the performance and false recent rates (FRRs) of the ARRA, interpreted both visually and via a strip reader, in comparison with the LAg-EIA. <b>Methods:</b> Plasma samples were collected from two groups: 634 long-term HIV-infected individuals, identified through routine diagnostic testing, who had not received antiretroviral therapy for over one year, and 224 individuals from high-risk populations. High-risk individuals, including pregnant women, female sex workers, and men who have sex with men, were selected based on behavioral and demographic risk factors. Concordance between the ARRA and LAg-EIA was assessed, and FRRs were calculated for both assays. McNemar's test was used to evaluate agreement, while Spearman's rho was applied to assess correlation between the two methods. <b>Results:</b> Visual interpretation of ARRA demonstrated perfect agreement with LAg-Avidity EIA results (FRR = 0.00%), while the strip reader misclassified two specimens as recent infections (FRR = 0.32%). McNemar's test indicated no significant differences between the methods (<i>p</i> > 0.05). Moderate agreement (Spearman's rho = 0.434) was observed between ARRA strip reader results and LAg-Avidity EIA optical density values. Among high-risk populations, ARRA misclassified one sample as recent, resulting in an inconsistency rate of 0.45%. <b>Conclusions:</b> This study highlights ARRA's reliability in identifying long-term infections and its potential as a point-of-care tool. Its rapid results and ease of use make it a valuable asset for effective HIV surveillance, facilitating targeted epidemic monitoring and enhancing public health interventions.