I had asked a similar question before. But now there's a little twist or something worrying.
I tested 12 weeks post PEP with a 4th generation ab/ag lab test which came back negetive. That was on the 25th of Sept. A couple of days after, i slept with my girlfriend without protection, with the assumption that the 12 week post pep is conclusive.
She is now having shortness of breath and constant phlegm on the throat.
How sensitive are these tests - would she be infected yet the tests couldn't pick up antigens or antibodies?