1. Errors in claim filing.
2. Improper insurance verification.
3. Coverage is no longer active.
4. Services not covered under insurance plan.
5. Services or treatment deemed not medically necessary.
6. The calendar year maximum has been reached.
7. Charges have been denied or reduced since pre- authorization was not obtained.
8. Charges have been limited to reasonable and customary charges.
9. The amount is above the fee schedule for the service.