Positive ana ifa screen with reflex is it contagious?

No: This isn't a screen for an infectious disease, and many people have a positive ANA yet are perfectly healthy -- in fact, there are probably more people in whom it's a non-finding than who have ANA-associated illness.

Antibodies: A positive ANA means antibodies which can react with your body's cells. They can form after an infection, but do not indicate anything about the infection which is usually long since gone. There are many, many people whose ANA is positive and very, very few who have actual autoimmune disease. The question to ask is: for what symptoms was the ANA ordered?