Is 4 weeks a good time to test for all stds after exposure?

6 weeks is better: Gonorrhea and chlamydia tests are valid any time more than 3-3 days after the last exposure, and negative results at 4 weeks will show you weren't infected. Same for certain vaginal infections, e.g. trichomonas. However, most other STDs require blood tests for diagnosis (e.g., syphilis, HIV, hepatitis B). Four weeks is pretty good, but they can take 6 weeks. Consider waiting another two weeks.