Medicare (Original / Part B): timely filing limit
Initial claim
12 months (1 calendar year) from the date of service
Clock starts from: date of service
Appeal window
120 days from the remittance date.
Caveats
Set by federal regulation at 42 CFR 424.44, not by contract, so this figure does not vary by Medicare Administrative Contractor. Claims denied for untimely filing carry no appeal rights for the timeliness issue itself; the 120-day figure is the standard redetermination (first-level appeal) deadline for a substantive denial, measured from the date of the initial determination.
Retrieved 2026-07-18.
Denied for timely filing already
See CARC 29 for the corrective actions and whether an appeal is worth filing.
DenialPath provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.