For example, syphilis-specific IgM cn be detected as early as 2 weeks after infection,[2] nontreponemal antibodies can be detected 5 to 7 weeks after initial infection, and both of these are generally correlated with disease activity.[3] The rabbit infectivity test (RIT) is another method used to establish infection with viable Treponema pallidum, and it has historically been considered as the gold standard for detecting active syphilis. This evidence concerns the gene CD40LG and infection.