I have been having trouble recently getting codes 92524, 92522, 92523 & 92507 covered through Gateway and Amerihealth. I used to use the modifier U9(which is what the biller before me used) with all of those codes except 92507, and they would all get paid but recently they are denying. So tried using modifier GN, but they are still denying. Even tried not using a modifier. Need help.