Inclusion Criteria:  Anonymized or pseudo-anonymized leftover samples from  Males or females Aged ≥18 years of age  Belonging to one of the following enrollment groups:  Unselected blood donor Hospitalized patient  Known HIV-1 antibody positive patients  confirmed positive by Immunoblot, Western blot or HIV-1/HIV-2 antibody differentiation test either at time of enrollment vai same study draw or historically from medical record  Known HIV-2 antibody positive patients  confirmed HIV-2 positive by BioPlex 2200 HIV Ag-Ab Assay  Known HIV-1 Ag positive patients  For samples from HIV seroconversion panels  Tested during EU HIV clinical trial: confirmed positive by screening HIV Ag/Ab combo positive for p24 Ag, and p24 Ag screening test positive (result from CoA or additional testing) Tested as part of seroconversion panel studies (V&V studies): First sample of the panel that is ARCHITECT Ag/Ab combo assay positive or BioPlex 2200 HIV Ag-Ab Assay p24 positive, and p24 Ag test positive (result from CoA or additional R&D testing)  For routine clinical samples:  Confirmed positive by screening HIV Ag/Ab combo assay positive for p24 Ag , and p24 Ag test positive by confirmatory test, or Confirmed positive by screening HIV Ag/Ab combo assay HIV positive, and p24 Ag test positive by confirmatory test and PCR HIV POS and IB/WB HIV negative or indetermined. with at least 2.0 mL leftover EDTA plasma sample from hospitalized patients OR at least 1.5 mL leftover EDTA plasma or serum sample from blood donors or known HIV-1 antibody positive patients, with confirmatory test already done as per inclusion criteria OR at least 1.0 mL leftover EDTA plasma or serum sample from known p24 Ag positive patients or known HIV-2 antibody positive patients, with confirmatory test already done as per inclusion criteria  Exclusion Criteria:  Samples from subjects already included in the study