I have heard so many times from friends that when you are Poz and you have blood group O, the results can come out Negative. How true is this? can HIV hide when blood group is O? please explain this to me.
What you heard "so many times from friends" is absolutely false. HIV doesn't care what blood type you happen to be, just as it doesn't care if you're gay, straight or bi-curious closeted Republican. HIV is a virus. It does not discriminate.