INTRODUCTION: Accurate and early HIV detection is crucial for improving outcomes and controlling transmission. This study compares HIV marker patterns and evaluates detection assay performance in general screening and ART-treated populations to enhance diagnostic accuracy and public health. METHODS: A total of 196 blood donor samples that were initially reactive in blood center screening were collected across 17 provinces in China, along with 126 ART samples from people living with HIV (PLWH). HIV RNA, Ag/Ab, and western blot were conducted in both groups. CD4 T-cell counts were assessed in PLWH. The performance of two antigen detection kits (Wantai, Livzon) and eight Ag/Ab kits (Roche, Abbott, KHB, InTec, Wantai, Livzon, Murex, Bio-rad) were evaluated. RESULTS: In the ART group, all samples were Ag/Ab positive, with 32.5 % (41/126) having undetectable viral loads
NAT-positive samples showed a higher rate of complete bands in western blot compared to NAT-negative group (42.5 % vs 15.4 %, P = 0.021), while p17, p39, and p31 bands were often absent. 90.8 % (178/196) of blood donors were NAT-positive and Ag/Ab-negative. 4.6 % (9/196) of blood donors were NAT-positive but Ag/Ab-negative, these samples were also tested as NAT-only reactive in screening at blood centers, often showing only a p24 band or negative result in WB, indicating early acute infection. 3.6 % (7/196) of blood donors were confirmed as NAT-negative but Ag/Ab-positive, hinting that a small group on ART might attempt to donate blood. HIV serological kits showed 100 % positivity in the ART group. Fourth-generation kits, particularly the Roche Ag/Ab kit, showed the highest sensitivity (95.2 %) for NAT-positive donors. DISCUSSION: This study highlights critical differences in HIV detection between ART-treated individuals and general screening populations, emphasizing the need for tailored diagnostic strategies to ensure blood transfusion safety.