Is the HIV swab test considered highly accurate?

[Gerlyn]

So today I went to the hospital with my Ex boyfriend because he had really bad asthma. As we were waiting in the waiting area for the doctor a lady who worked at the hospital was offering free HIV test so I decided I would take it, so my Ex boyfriend did also. It was an swab HIV test which means that it was with the saliva in your mouth now the crazy thing out of all this is that I came out Negative. But he came out positive so the lady redid the test on him and the second time it came out positive as-well. She had told us to not freak out because last week two women had went to get tested also and they had came out positive with the swab test but when they did the blood test one of them found out she had herpes and the other one an infection. They also did his blood test but we have to wait till next week. I'm a little scared because he confessed to me that he had unprotected sex about last week with his other Ex. What can it be? HELP PLEASE & THANK YOU...