Thank you for your inquiry. From what we gather from the question, you were asking about the risk of acquiring HIV after engaging in oral sex. For the purpose of this answer, I will assume the highest risk scenario in which you were the individual performing unprotected oral sex. From the information given, this scenario is determined to be Low Risk (evidence of transmission occurs through these activities when certain conditions are met).
The scenario mentioned above could meet the three components of the transmission equation if bodily fluids containing the HIV virus, such as blood, vaginal fluid, or semen, gained direct access to you bloodstream through a mucous membrane or an open wound. Please note that if you were the individual receiving unprotected oral sex your risk assessment would be Negligible Risk because saliva is not a bodily fluid that can contain the HIV virus. The assessment is not "no risk" because there is a theoretical possibility of transmission under certain extenuating circumstances (large amounts of blood present in the saliva), but there are no documented cases of transmission.
The testing you accessed is considered conclusive 3 months post-exposure, thus both of the negative results you received are accurate (1).
Recommendation: In the case of a low risk scenario, no further testing is required as testing has been accessed outside of the window period. Refer to a healthcare professional for more personalized answers.
AIDS Vancouver Helpline/Online, Marie
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1) HIV Testing Technologies