Sir. After exposure ,i have done the 4 gen combo test 4,5,6,7 weeks and then on 90 th day ,105 th day and finally 156 th day. The results are negative. The kit used is artichet hiv ag/ab chemiluminescent developed by abbot laboratories. Those results are conclusive? What about the 6 month delay period? Should I need to take a test after 6 months? What is the specific advantage of 4th gen combo test as they say it can pick up recent infection sonner. Then what about out of window period? This can be reliable detecting the virus later, that is if one gets infected as the normal antibody test might not able to pick up infection?