Structure
Find your MAC through CMS. Your MAC issues local coverage determinations (LCDs) that affect medical necessity in your region: two practices in different MAC jurisdictions can get different answers on the same service.
Enrollment
Through PECOS:
Expect 60–120 days. Ownership and managing control disclosure on the 855B requires care in an MSO-PC structure: see Enroll in Medicare.
On approval you receive a PTAN, a MAC-assigned identifier distinct from the NPI. Record group and individual PTANs.
Timely filing
12 months from the date of service: set by statute and regulation.1 One of the few limits that is fixed rather than contractual.Appeals: the five levels
Each level has its own deadline; levels 3 and 5 have amount-in-controversy thresholds. Most provider appeals resolve at level 1 or 2.
Revalidation
Every five years for most providers (three for DMEPOS). Notices go to the correspondence address in PECOS: if nobody monitors it, the first you’ll hear is when billing privileges are deactivated and claims stop. Check your date directly in the Medicare Revalidation Lookup Tool.Quirks worth knowing
- Sequestration appears as CO-253, a statutory payment reduction. Write it off.
- Opt-out physicians cannot reassign benefits to your group: check status during clinician vetting
- Incident-to and split/shared rules are Medicare-specific and frequently misapplied
- Crossover to secondary payers is automatic for many claims: submitting the secondary separately produces duplicate denials
- The 60-day overpayment rule applies to Medicare. See Report and return overpayments.
Sources
- Social Security Act § 1842(b)(3)(B); 42 C.F.R. § 424.44. CMS, Medicare Claims Processing Manual.