CMS clarified in 2007 that a physician practice may bill Medicare patients for failing to keep an appointment.  The CMS MedLearn matters article is attached as a resource.

Check with your state Medicaid to see if you can bill Medicaid patients.

If you are billing Medicare patients, this must be your practice's policy, to bill all patients for missed appointments.  The amount charged to the Medicare beneficiary must be the same as to other patients for a missed appointment.

The MedLearn Matters article instructs clinicians that they may bill the beneficiary directly (Medicare does not pay.)