Hi Mateo. As with virtually all HIV rapid tests, the BioSURE HIV Self Test looks for antibodies to HIV, rather than the virus itself. If a person has produced antibodies then the test will detect them, but because of how immune systems work, people produce these at different times and rates after contracting the virus. Most people have made these antibodies by 4 weeks but some people can produce them as late as 12 weeks later. This is why we say a negative result cannot be relied upon within this period and it is recommended to test again at 3 months after exposure. A positive test result can always be relied upon as it means antibodies to HIV have been detected. If you feel at all uncomfortable as your exposure is within the last 3 months then we would recommend you visit a clinic that can offer you a laboratory based test. I hope this helps. Kindest regards Francesca Bard, BioSure (UK) Ltd