When is a negative test accurate? if it been 27 days since sexual activity and got negative on pregnancy tests repeatedly, is this accurate?

Maybe. It depends on if it was done correctly, which is hard to do wrong. The hormones of pregnancy are usually present 2-3 weeks after sex that triggers pregnancy. If a test done correctly at 4 weeks, it should be positive if there is a pregnancy. That said, these tests are occasionally falsely negative early in pregnancy. They are rarely ever falsely positive.

If you did the test correctly, it is accurate. If you have any doubt, get a blood test for HCG level to settle the issue. Get HPV vaccine. Wish you good health! Safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines