Performance of the VISITECT(R) CD4 Test for Rapid Identification of Advanced HIV Disease at AHF-Supported Sites in Zambia: A Diagnostic Accuracy Analysis in a Zambian Population

BackgroundAdvanced HIV disease (AHD), defined as a CD4 count below 200 cells/mm3 or the presence of WHO Stage 3 or 4 clinical conditions, poses significant diagnostic challenges in resource-limited settings such as Zambia. Early identification of AHD is essential for improving outcomes for recipients of care (ROCs). The VISITECT(R) CD4 test, a point-of-care tool, offers potential for addressing these challenges; however, its diagnostic performance in Zambia remains under-evaluated. This study aimed to assess the sensitivity and specificity of the VISITECT(R) CD4 test for identifying AHD among ROCs at five AIDS Healthcare Foundation (AHF)-supported clinics in Zambia. MethodologyA cross-sectional study was conducted between January 8 to May 31, 2024, at five AHF-supported clinics in Zambia. Participants included individuals who were newly diagnosed with HIV, re-engaging in HIV care, or presenting with unsuppressed HIV viral loads. Baseline clinical and demographic data were collected, and the diagnostic performance of the VISITECT(R) CD4 test was compared to the flow cytometry CD4 test (the gold standard) using STATA v15 to determine sensitivity, specificity, and other diagnostic accuracy metrics. ResultsAmong 231 participants, 24.7% (57/231) had AHD based on the flow cytometry CD4 test, whereas 47.6% (110/231) were classified with AHD by the VISITECT(R) CD4 test. The VISITECT(R) CD4 test demonstrated a sensitivity of 96.5% and a specificity of 68.4%. The Negative Predictive Value was 98.4%, and the Positive Predictive Value was 50.0%. The overall diagnostic accuracy, as indicated by the area under the curve, was 0.82 (95% CI: 0.78, 0.87). AHD was significantly associated with age according to flow cytometry (p=0.029) but not according to the VISITECT(R) CD4 test (p=0.277). A significantly higher proportion of individuals with anemia had AHD across both tests (p<0.05). ConclusionThe VISITECT(R) CD4 test demonstrated strong diagnostic accuracy for detecting AHD, making it a valuable rapid point-of-care tool in resource-limited settings. Its wider implementation could enhance early AHD detection and facilitate timely clinical interventions, warranting further exploration.