Even if the syphilis test is negative, it is still necessary to check for syphilis later in life if other symptoms are present. After a 2-4 week incubation period, the first damage that occurs at the site of invasion is called stage 1 syphilis, or hard chancre. Due to the body’s ability to resist, some of the syphilis spirochetes are eliminated and the damage gradually fades into latent syphilis. At the same time, another part of the spirochete gradually enters various parts of the body and develops various clinical symptoms, called stage 2 syphilis, which can subside on its own without treatment and enter the latent phase again. The latent syphilis test can be negative.