Had Oraquick Oral Swab Hiv-1/hiv-2 Test Done At 3 &

Had oraquick oral swab hiv-1/hiv-2 test done at 3 & 4 weeks and both times was negative. I had tests because I performed oral sex on an hiv + undetectable guy (been undetectable for a year). No bodily fluids were exchanged but how reliable is this test at 4 week mark?