Hi Thakur Thanks for getting in touch. Firstly all negative HIV tests should be considered to be encouraging, but this needs to be considered in conjunction with the defined window period for the test taken. Given that your last test was a 4th generation test this should be conclusive, but suggest that you may get more information by contacting the testing centre that performed the test for you. 3rd generation HIV rapid tests are generally very accurate and CAN detect HIV from about 24 days after infection. However, 3rd generation tests look for antibodies so should still be considered to have a window period of 3 months. Whilst most people will have created antibodies to HIV after 24 days some may not until 3 months after infection. So to be certain of a negative result you would need retest 3 months after possible infection. Secondly, the chances of contracting HIV from insertive unprotected oral sex is incredibly low, even from someone who is HIV positive. With someone of unknown HIV status at least 100 less likely. I hope that this helps. Kind regards Gary Carpenter BioSure (UK) Limited