I live in the us, how common is it for me to get hepatitis b from a blood transfusion?

Rare. The chance to get transfused with hepatitis b contaminated blood product is estimated at 1/63, 000 - 1/500, 000 per unit of product.
Very uncommon. These days blood donors are screened carefully. It was much more common in the 80's.

Related Questions

How to treat Hepatitis B? I've got blood transfusion and they detected hep B in it. They couldn't test it earlier because it was emergency.

Need more info. More than 80% of the patients with hepatitis B infection recover on their own and eliminate the virus and are none the worse for it. You may wish to get tested in about six months to see if you have active infection or have recovered. God forbid you have chronic infection, it can be treated. Wish you good health. Read more...