Evaluation of the diagnostic validity of the HIV VISITECT CD4 point-of-care rapid diagnostic test in Uganda.

BACKGROUND

HIV remains highly prevalent in Uganda, where CD4 T-cell counts are central to identifying and managing Advanced HIV Disease (AHD). Instrument-based point-of-care (POC) CD4 platforms face cost and operational constraints in resource-limited settings. The VISITECT CD4 lateral flow immunoassay (LFA) offers a non-instrument-based alternative, but its diagnostic validity against the Pima Analyzer had not been evaluated in Uganda.

OBJECTIVES

To compare diagnostic validity of the VISITECT CD4 LFA against the Pima Analyzer at the 200 cells/µL AHD threshold and explore factors influencing performance.

METHODS

A comparative cross-sectional study was conducted between June and August 2023 at three Kampala health centres. Venous blood from 351 HIV-positive adults was tested simultaneously on both platforms. Sensitivity, specificity, PPV, NPV, and likelihood ratios were calculated with 95% CIs using the Pima Analyzer-a point-of-care, not gold-standard, platform-as reference; estimates reflect relative, not absolute, performance.

RESULTS

Most participants were female (68.11%), median age 31 years; mean CD4 count was 482 cells/µL (± 283.9) and AHD prevalence 22.79%. VISITECT CD4 LFA showed sensitivity of 86.25% (95% CI: 76.73-92.93), specificity of 90.41% (95% CI: 86.26-93.64), PPV of 72.63% (95% CI: 64.57-79.44), NPV of 95.70% (95% CI: 92.78-97.48), and inter-rater agreement κ = 0.957. No assessed factor significantly modified performance.

CONCLUSIONS

The VISITECT CD4 LFA performed reliably as an AHD screening tool relative to the Pima Analyzer in resource-limited settings, particularly where instrument-based platforms are unavailable. It should complement, not replace, confirmatory testing; improvements in sensitivity and PPV remain warranted.