These include duplicate claim submissions, services performed by unqualified employees, or missing prior authorizations for certain equipment. The Appeals Process

Most denials can be traced to preventable administrative or clinical documentation issues:

If a claim is denied, you have a legal right to appeal the decision. For Original Medicare (Part A and B), there are five distinct levels of appeal: Medicare Program Integrity Manual, Chapter 6 - CMS

The most frequent cause is simply failing to submit requested progress notes or medical records.