Hi Goingmad, The fact that you have taken a BioSURE self test a few years after a possible exposure and the result came back as negative is a really strong indication that you are HIV negative. Often when people test years after an exposure, if they were to be positive, the test line would be very strong and visible to the user. False negatives do occur but these are still very rare and occur most often when users test inside of the window period. Given your two negative results using our test, I would say that a lab blood test is not necessary but if it may help to put your mind at rest, it may be worth looking into. The chances of 2 negative results being false when testing around 2 years post exposure, is around 1 in a million. I hope this helps, please leave a comment below if you would like me to answer some more queries. Becky