My boyfriend was told in September that he was HIV positive. In July and August, he received STD test, which both came back negative. Now, the doctors are saying that he has full blown AIDS and that his CD4 count is twelve. They have told him to prepare for the worse, but I am wondering how is this at all possible. Why if he has AIDS did his test in July/Aug come back negative? And if his cd4 count is so low why is he not experiencing any symptoms or illness? Is this possibly a misdiagnosis or is this situation possible?

I am somewhat confused by your question. You said that he had an "STD" test in July and August. What kind of STD was he tested for? HIV is one of many STDs. If you meant to say that he had an HIV test in July and August, which were negative, but then positive in September - it is possible for these tests to have been accurate. Although, it would be somewhat unusual for someone to have such a low CD4+ count so shortly after seroconverting, but not impossible. Someone can also be asymptomatic with a very low CD4+ count, but if the low count were to persist, that person would probably not remain asymptomatic.

The bottom line is that your boyfriend needs to continue with close monitoring and care from a qualified HIV physician. It also sounds like you could benefit from discussions with a physician (whether that be your boyfriend's or your own) so that you come to understand the issues involved.