Hi Biggy The issue here is not really about which test you use but about the risk of relying on a negative test during the early stages of infection. The risk here is pretty much entirely down to the individual's reaction to the infection. This is the largest factor in the variation. A positive test result is equally reliable pretty much whenever you test. Also, for most people it is quite difficult to pin down one specific possible exposure to HIV. Most people, i.e. just over 50%, will have antibodies by 21 days that are detectable by antibody tests. The BioSURE HIV Self Test would be around 5 days behind this. So 50% by around 4 weeks. Around 95% by 6 weeks (true for all tests, probably not 4 weeks) and everyone by 12 weeks. So regardless of the test you shouldn't absolutely rely on a negative result earlier than 12 weeks post exposure. With regard to sensitivity between generations there is no difference. I hope that I've answered your questions. Please don't hesitate to get in touch if you need any more information. Kind regards Gary Carpenter BioSure (UK) Limited