Nobody on here has ever said that RNA tests are not approved diagnostic tests. You probably read a comment about DNA tests, which are not approved, and got confused.
My understanding was that RNA tests at King County are used in combination with antibody tests, but maybe that has changed. The antibody test was still used as a safety measure, because the RNA testing is so new. See the thread below from Dr. HHH that explains the program:
http://www.medhelp.org/posts/HIV-Prevention/Further-testing-required/show/550794
I agree that RNA should show positive at two weeks if someone is infected, which is the peak of the viremic phase. However, I believe that the manufacturers of the RNA test do not recommend it as a stand alone test, hence the recommendations on this forum. You can probably find more information on that in this forum from one of Teak's threads.
I personal think that it is a complete waste of resources for you to get an RNA test over oral sex. However, from rereading Dr. HHH's summary of the program, you may qualify because you are in a high risk group.
Both doctors here consider oral sex to be virtually zero risk, and there are several other websites that support the same view (SF City Clinic, Johns Hopkins). But if you'd rather believe the CDC then this website then please do not continue to post here.