I had exposure (mutual masturbation and titsex) with a sex worker two years ago. No oral, vaginal or anal sex took place. Oil was used on my penis and her breasts for lubricating. Half a year later I received a HIV screening (4th gen) along with my physical, which came back non-reactive. Should I retest due to possibility of false negative?
Thank you for your inquiry. From what we gather from the question, you were asking about the necessity to be retested for HIV due to the possibility of a false negative. From the information given, you received a 4th Generation test 6 months after a possible exposure. A 4th Generation test at 6 weeks is considered to be conclusive and 99.9% accurate. If the 4th generation test is negative, the person is considered to be HIV-uninfected and no further testing needs to be done. 
Recommendation: From the information given, this scenario is determined to be no risk.
Regards, AIDS Vancouver Helpline/Online, Ashley
- Bartlett J, Sax P. Screening and diagnostic testing for HIV infection [Internet]. Uptodate.com. 2018 [cited August 15 2018]. Available from: https://www.uptodate.com/contents/screening-and-diagnostic-testing-for-hiv-infection?search=HIV%20test&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H3828426