HIV-2 will test positive on today's 4th generation antigen/antigen testing, and the confirmatory antibody differentiation assay will identify it as HIV-2.

If you test HIV-2 by routine commercial PCR test, however, it will be negative. That's because routine commercial PCR tests only for HIV-1, while the HIV-2 PCR is a separate PCR order/test (and is a send-out at most centers in the US).