If you have a reason to suspect a possible infection of yourself or your sexual partner(s), it is wise to take a test. We advise you to wait 3 months before you do a test because although most people will manifest antibody levels within 30 days, a significant percentage do not show these anti-bodies until about 90 days.
The National CDC has said that in some rare cases, it may even take up to six months for one to be tested positive. At this point, the results will be 99.9% accurate. We recommend you do 2 tests 30 days apart.