I tested HIV in hospital, I really don't know which generation of test paper they use, could it be 2 generation? if it is true, the window period would be much longer,and when HIV get into a person's body, how long does it takes util the HIV antibody produced? how much the antibody should produce until it could be detected by the test paper? is the test paper reliable? what is the possibility that the results turn negative into positive? Thanks!