Hi Antibodies, The BioSURE HIV self test can accurately detect infection 12 weeks post exposure. At 4 weeks, 50% of people will have produced enough antibodies. At 6 weeks, 95% of people will have produced enough antibodies and by 12 weeks, it is 99.9% of people. You can test at any time during the window period but would always need to retest 12 weeks post exposure for a conclusive result. The accuracy of the test is 99.7% and does not change throughout and after the window period but it just depends on your body's ability to produce antibodies. I hope this information helps. Kindest regards Becky