HIV p24 is a viral protein encoded by the HIV-1 gag gene that provides structural elements of the virus along with p6, p7 and p17. Specifically, p24 makes up the viral capsid.
The p24 antigens are a part of the virus, and research indicates that they tend to appear within 2 weeks of HIV entering the body.
4th-generation HIV tests can detect both HIV antibodies and p24 antigens. 4th-generation tests detect the virus as soon as applied, which allows for earlier treatment. | 
