Performance Evaluation of a Novel RapiSafe HIV Ag/Ab Combi Rapid Test for the Detection of HIV Antigen and Antibodies

Zhonggang Fang^1*Wenzhao Luo^2*Shuai Wei^3,4Zhongyuan Huang⁵Kun Liu¹Qiang Huang^3,4Chen Lan³Qunxian Zhang³Liuling Liu⁵Jun Yin¹Weiting Li¹Yongsheng Xiang¹Pengpeng Zou¹

• ¹Research & Development Department, Shenzhen New Industries Biomedical Engineering Co., Ltd. (Snibe), Shenzhen, China
• ²Department of Infectious diseases, Hechi Hospital Affiliated to Youjiang Medical University for Nationalities, Hechi,Guangxi, China
• ³Department of Clinical Laboratory, Hechi Hospital Affiliated to Youjiang Medical University for Nationalities, Hechi, Guangxi, China
• ⁴Modern Industrial College of Biomedicine and Great Health, Youjiang Medical University for Nationalities, Guangxi, China
• ⁵Department of Infectious diseases, Hechi Hospital Affiliated to Youjiang Medical University for Nationalities, Hechi, Guangxi, China

Background: The detection of acute HIV infection (AHI) is vital for timely diagnosis and appropriate management, thus, in vitro diagnostic tests that accurately identify antigen and anti-bodies separately, have a short seroconversion window period, rapid turnaround time are essential. This study aimed to evaluate the analytical and clinical performance of the RapiSafe rapid test, with a particular focus on its efficacy in detecting AHI in serum samples. Methods: Antigen sensitivity was evaluated in 1st WHO International Standard for HIV-1 p24 Antigen (NIBSC 22/230) and Reference Panel (NIBSC 16/210). Five HIV-1 seroconversion panels and one HIV-1 p24 antigen Mixed Titer Performance Panel were detected for HIV-1 p24 antigen This is a provisional file, not the final typeset article seroconversion sensitivity evaluation. 22 treatment-naïve acute HIV-1 serum at Fiebig stage III-VI were detected with both the RapiSafe and the Determine tests. To evaluate the diagnostic sensitivity in different genotypes and specimen types of HIV-1 established infections, HIV positive serum and venous whole blood were detected. Diagnostic specificity was evaluated in clinical serum, plasma, capillary whole blood, and venous whole blood. Results: Compared with the Abbott Determine tests, the RapiSafe showed lower antigen detection limits in HIV-1 subtypes A1, C, and D; higher p24 antigen sensitivity with five more seroconversion reactive detections; and one more antigen-positive AHI serum detection. The superior antigen and antibodies sensitivity of the RapiSafe among serum, plasma, and venous whole blood did not compromise specificity (99.75-100%) among different specimen types with potentially cross-reacting substances or unrelated medical conditions. Conclusion: The exceptional performance of the RapiSafe in antigen and antibodies detection among different subtypes and specimen types makes it a valuable tool in HIV diagnosis. Its novel approach could significantly impact global HIV control by facilitating early detection and timely intervention, which are essential for the uptake of prevention, prompt HIV diagnosis, and mitigating global HIV transmission risks.