Hi Adzy8901, I apologise for not getting back to you sooner. At 4 weeks, 50% of people will have produced enough antibodies for the BioSURE HIV Self Test to be able to accurately detect infection. At 6 weeks it has been proven that 95% of people will have produced enough antibodies. I am unsure of the exact percentage at 5 weeks but everyone produces them at different rates so it is hard to say for sure. A negative result at 36 days is a good indication of your status however you must retest at 12 weeks for a conclusive result. The BioSURE HIV Self Test is 99.7% accurate - the accuracy of the test does not differ throughout/after the window period, it just depends on whether the user has enough antibodies in their blood to accurately detect infection. I hope this helps, if you have any other questions please feel free to leave them below in the thread. Kindest regards, Becky