I have provider who is reporting an e&m service (99220) the day prior to AND the day of a major surgery. The provider is appending the e&m code the day of surgery (99232) with mod 57. Is this correct? The observation visit record states "will observe for now, but if not better in the a.m., will consider surgery" The next day, the provider performs an appendectomy. Should both services be allowed? If not, which service should have the -57 modifier?