4. The administrator will guide the tester to use the oral fluid based HIVST kit correctly. The HIVST kit to be used in this study (AwareTM Oral) is a brand of the Calypte Biomedical Corporation of the U.S., and is being manufactured by a subsidiary company of the Calypte Biomedical Corporation in Beijing. It has a proven sensitivity/specificity of >99.8% and has been approved for marketing by the State of Food and Drug Administration (SFDA) in China. It is now being used by CDC in China nationwide. This kit is available online at a price of 200HKD. The project team can obtain the kits at a discounted price at 80HKD per kit (liaison has been made with the manufacturer).