# Developing and evaluating a novel rapid test for recent HIV-1 infection: comparison with commercial LAg-EIA assays

## TL;DR

A new rapid test for recent HIV-1 infections was developed and evaluated, showing strong performance and potential for use in resource-limited settings.

## Contribution

A novel rapid HIV-1 recency test was developed for point-of-care use, offering simplicity and rapid results.

## Key findings

- The rapid test had a mean duration of recent infection of 123 days, shorter than two commercial assays.
- False recent rates were comparable to existing assays, with higher rates in early ART-treated individuals.
- High concordance was observed with commercial LAg-EIA kits, indicating strong agreement.

## Abstract

Accurate identification of recent HIV-1 infections is critical for real-time epidemic monitoring. However, conventional Limiting Antigen Avidity Enzyme Immunoassays (LAg-EIAs) are restricted to laboratory settings. A novel rapid recency test based on the limiting antigen avidity principle was developed for point-of-care use. We evaluated the performance of the rapid HIV-1 recency test using 500 longitudinal plasma specimens from 107 seroconverters. The mean duration of recent infection (MDRI) was estimated via binomial regression with maximum likelihood modeling. The false recent rate (FRR) was assessed using samples from individuals with long-term infection, including those on antiretroviral therapy (ART). Concordance was compared with two commercial LAg-EIA kits (Maxim and KingHawk). The rapid assay yielded an MDRI of 123 days (95% CI: 87–138), shorter than Maxim (152 days, 95% CI: 137–172) and KingHawk (131 days, 95% CI: 107–140). Among ART-naïve individuals infected for over 1 year, FRR was 5.3%, similar to Maxim (5.9%) and slightly higher than KingHawk (2.7%). High concordance was observed with Maxim (93.1%, kappa = 0.743) and KingHawk (89.4%, kappa = 0.558). In ART-treated individuals, FRR was significantly higher in the early ART group (69.9%) compared to the late ART group (20.2%, P < 0.001). The novel rapid HIV-1 recency assay demonstrates acceptable MDRI and FRR and strong agreement with commercial LAg-EIA kits. Its simplicity and rapid turnaround make it a promising tool for decentralized surveillance and targeted HIV interventions, especially in resource-limited settings.

Rapid detection of recent HIV-1 infections is essential for monitoring ongoing transmission and guiding targeted prevention efforts. However, currently used laboratory-based recency assays require specialized facilities and trained personnel, limiting their use in decentralized or resource-limited settings. In this study, we evaluated a newly developed rapid test that identifies recent HIV-1 infections within minutes using a simple, instrument-free format. The test showed strong agreement with two widely used laboratory assays and demonstrated performance suitable for surveillance applications. Its ease of use, rapid turnaround, and minimal infrastructure requirements make this rapid test a practical tool for expanding real-time HIV monitoring and improving the efficiency of public health responses.