CD40LG and infection: First- and second-generation assays detect IgG against HIV-1 infection at approximately 6–10 and 4–6 weeks, respectively.15 The third-generation assay also detects IgM and IgG against HIV-1, and a diagnosis can be made from 3 weeks post-infection.16 Around 2010, the newer fourth-generation assay replaced third-generation tests by combining the detection of early p24 and HIV antibodies (IgM and IgG).