The number of weeks to rule out syphilis varies from person to person and is usually 8-12 weeks. Syphilis is a sexually transmitted disease caused by infection with the syphilis spirochete. After entering the body, the syphilis spirochete stimulates the body to produce specific antibodies. This antibody can be detected by immunological methods, usually 3-4 weeks after infection. If the test is negative at 8 weeks, it can be repeated at 12 weeks and if it is still negative, it can be ruled out in most cases. However, in some patients, antibodies may be produced later than 12 weeks and may even be negative (mostly false negative) when early syphilis symptoms are present. In this case, regardless of whether the antibodies are positive or not, syphilis should be treated as such. Syphilis is most often contracted after high-risk sex, so it is recommended that 3-4 weeks after having high-risk sex, you should promptly seek medical attention from the infection department or STD department to test for infection. If the test is positive, the patient should be treated aggressively; if the test is negative, the patient should be tested again at 8 or 12 weeks.