I know you get this a lot, I took a 4th gen hiv antigen/antibody test 161 days after an incident with a massage therapist.  The result was negative.  Is this 100% conclusive do I need to go back for any follow up testing?

Welcome back, but sorry you decided to spend a posting fee when you apparently have seen our multiple replies to similar questions. Of course that information applies to your situation as well. The Ag-Ab HIV blood tests ("4th generation") are 100% conclusive within a few weeks of the last exposure, usually after 4 weeks and always at 6+ weeks. For sure your negative result at about 5 months is conclusive and no additional tests are needed.---