The guidelines are 12 weeks, and that is also one of the reasons we advise testing at that time too.
Below are also some statements from Dr HHH. You might be interested to read them.
I also have other comments from other doctors who have advised people to get tested at 3 months. Doctors who have at times also said the DUO is conclusive at 4 weeks.
They say conclusive according to their own assessments of different risks. As members ((non-professionals)), we don't have that privilege and should consider all risks as high risks and advise a confirmatory 12-week test.
Actually, if you read the link you yourself have provided carefully, you will also see some reasons why a 4th gen may not be enough at 4 weeks.
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Dr HHH:
"it is sometimes wise to have an extra test at the lastest possible time. We do the same thing here. Even though we almost always say 6-8 weeks is plenty of time, when someone is at particularly high risk, WE ADVISE TESTING AT 3 MONTHS."
"assume a known HIV infected partner has unprotected anal sex. The receptive partner has a 1% chance of catching HIV, or 1 in 100. If a test at 4 weeks is negative, his chance of being infected drops to 1 in 1,000. A lot better than 1 in 100, but obviously not good enough. Same test, done at the same time after exposure, but a very different level of reassurance. This person clearly needs another test or two. Even at 6-8 weeks, when the test picks up nearly all (let's say 99%) of infections, the chance he has HIV is still 1 in 10,000. Better still, but good enough? Maybe not. THEREFORE, DOCTOR HOOK OR I WOULD RECOMMEND A 3 MONTH TEST.
You can find the above quotes from Dr HHH in the link below:
http://www.medhelp.org/posts/HIV---Prevention/Hi--Help-discuss-some-questions-i-have/show/1177982
