I have a general question whether antibiotics affect blood testing. The blood tests could be for immune markers or to test for more infections etc. etc. Should one stay off antibiotics before blood testing & if so for how long? My doctor found an active bacterial infection & would like me to take antibiotics for it. But, I am also scheduled to see another doctor to get tested for viral infections & immune markers etc. So, I am thinking out loud on what would be the best course of action. Please advice. Thanks.