What was your risk, oral, anal or vaginal and did you use condom?
Your exposure would be good to have. If could share that please.
But in general, if you took a duo test, that is a 4th generation test. 4 weeks after your exposure, a duo test is 98% accurate.
Third Generation of HIV tests only looks for the body's response to HIV infection - Antibodies.
Fourth Generation of HIV tests are advance, they look for antibodies and also a core viral protein called - p24 antigen.
Your test was a fourth generation HIV test and you have tested conclusively negative.