Why would I be going to Hell just because I got a blood transfusion?

My dad was telling me about a certain belief system that thinks if you get a blood transfusion you go to Hell because when you get saved you blood is clean, and when you get a transfusion you get someone else's blood who is presumably not clean and you cannot ask for that blood to be made clean. Why would that be true when the Bible says that if you love the Lord with all your heart, soul, and mind you go Heaven, it mentions nothing about the state of your physical blood.