Hello Let me explain whole thing , this may help you. Oral sex is less efficient mode of transmission of HIV infection. A number of studies have reported that the incidence of transmission of HIV infection by oral sex among couples discordant ( both male and female i.e. homo or hetero) for HIV is extremely low ; indeed one study reported no cases among 239 men whose only risk was receptive oral intercourse where 28 % knew that their partner was HIV-infected ( but in your case even you don t know the HIV status of your partner , even HIV infected can t transmit HIV to others). However , there have been several reports of documented HIV transmission RESULTING solely from RECEPTIVE FELLATIO and insertive cunnilingus .There are so many more cases that go unreported because of the frequent practice of both oral & receptive anal intercourse by the same person( as in your case you mentioned that it was only oral sex , so this is assumed that your right so nearly no chance of getting HIV by you). Therefore , the assumption that receptive oral sex is completely safe is not warranted . So I recommend you get in P 24 rapid NUCLEIC ACID AMPLIFICATION test ( pcr , rna as you mentioned ). Antibodies to HIV begin to appear within 2 weeks of primary infection ( contract with partner ) and development of detectable antigen for antibodies is not later than 3 months . So in your case , deal as I mentioned for confirmation ( WESTERN BLOT is most specific and sensitive and accurate test (99.5% ). Hope this will help you.