ClaimetryX revenue cycle knowledge platformClaimetryX™
Denial Knowledge Center

CO-29 — Timely Filing Limit Expired

The claim was received by the payer after the deadline allowed in the plan/contract (or, for Medicare, after the 12-month statutory limit), so it is being denied for lateness rather than for any clinical or cod…

← All denials
D11
Resolves: Billing/Denials Follow-Up
Prevents: Health Information Management/Coding (charge-lag reduction) and Patient Financial Services (workqueue aging controls).
Primary CARCCO-29

Denial Identifier

  • Primary CARC: CO-29 — "The time limit for filing has expired." (X12)
  • No single RARC is fixed to this CARC; combinations vary by payer, and some payers add an alert-type remark referencing appeal/reopening rights. Do not assume a specific RARC always accompanies CO-29.
  • For Medicare specifically, the general rule is 12 months (1 calendar year) from the date of service, per 42 CFR §424.44, with limited administrative-error and retroactive-entitlement exceptions (CMS Medicare Claims Processing Manual, Ch. 1, §70). Non-Medicare payer timely- filing windows vary by contract and must be verified per payer.

Plain-Language Meaning

  • The claim was received by the payer after the deadline allowed in the plan/contract (or, for Medicare, after the 12-month statutory limit), so it is being denied for lateness rather than for any clinical or coding reason.

Why the Claim Was Denied

  • Claim construction/Billing: claim held in a work queue too long before submission; clearinghouse rejection not caught and corrected in time
  • Registration/Eligibility: delayed retroactive eligibility determination pushed the effective submission date out
  • Payer processing: claim was submitted timely but rejected as unprocessable, and the corrected version was not resubmitted within the remaining window

Information the Biller Must Review

  • Date of service, original claim submission date and proof (clearinghouse acceptance report, certified mail receipt, EDI acknowledgment), payer-specific timely filing limit (verify per contract for non-Medicare payers), any applicable exception documentation (administrative error, retroactive entitlement).

What Needs to Be Corrected

  • Claim correction: Generally none — a true timely-filing denial is not fixed by editing claim data.
  • Upstream correction: The workflow that delayed submission (charge-lag, coding backlog, eligibility-verification delay) must be fixed to prevent recurrence; for Medicare, an exception request requires documented proof of one of the specific regulatory exceptions.

Resolution Workflow

  • Confirm the actual date of service and the payer's specific timely-filing limit.
  • Gather proof of original timely submission (acceptance report, transmission log).
  • If proof of timely submission exists, submit that proof to the payer as a claim- status/processing dispute rather than a new appeal.
  • If genuinely late, determine whether a recognized exception applies (for Medicare: administrative error, retroactive Medicare entitlement, retroactive MA/PACE disenrollment) and gather the required documentation.
  • If no exception applies, the claim is closed as a write-off; per Medicare policy, a claim denied solely for untimely filing is not an appealable initial determination.
  • Document the timely-filing analysis and root cause.
  • Escalate to Patient Financial Services/leadership if the delay traces to an internal process failure requiring workflow redesign.

Corrected Claim vs Appeal vs Other Action

  • Payer follow-up (proof of timely submission) — when the claim was actually submitted on time but the payer's received-date record is wrong.
  • Compliance/administrative-error exception request — Medicare only, and only under the specific regulatory categories.
  • Write-off/contractual adjustment — the typical outcome when no proof of timely submission or valid exception exists.
  • Formal appeal — under Medicare rules, a denial based solely on untimely filing is generally not subject to the standard appeals process; verify current payer-specific rules before advising otherwise.

Do Not Do This

  • Do not bill the Medicare patient for services denied solely as untimely filed, except for the deductible/coinsurance that would have applied had the claim been paid, when the beneficiary was not responsible for the delay.
  • Do not backdate a claim submission record.

Department Most Likely Responsible

  • Resolves current claim: Billing/Denials Follow-Up. Prevents recurrence: Health Information Management/Coding (charge-lag reduction) and Patient Financial Services (workqueue aging controls).

Prevention Control

  • Timely-filing workqueue with aging alerts well before the deadline; charge-lag monitoring from date of service to claim submission; clearinghouse rejection dashboards to catch and correct claims before the filing window closes.

Escalation Trigger

  • Internal system or process failure caused the delay (compliance-relevant); a Medicare regulatory exception category may apply and needs contractor-level review; payer disputes proof of timely submission.

Sample Scenario

  • Scenario: Claim denied CO-29, Medicare, submitted 13 months after date of service.
  • Finding: No administrative error or retroactive-entitlement exception applies; claim was simply delayed in a coding backlog.
  • Action: Claim written off as a timely-filing loss; coding backlog escalated to HIM leadership to prevent recurrence.

Resolution path at a glance

IdentifyAssign ownerCorrectResubmit / AppealPrevent

AI Search Terms / Synonyms

  • CO29; CO-29; timely filing denial; filing deadline expired; late claim submission; 12-month rule.

AI Answer Guardrail

  • Verify the specific payer's timely-filing deadline (Medicare's 12-month rule under 42 CFR §424.44 is not universal) and confirm whether documented proof of timely submission or a recognized exception exists before recommending any action beyond write-off.

Sources

  • X12 CARC list; CMS Medicare Claims Processing Manual, Chapter 1, §70

Validated ClaimetryX Source — Denial Management Knowledge Base, 2026 Research Edition

Research date August 18, 2026. CARC/RARC combinations and payer processes vary. Always check the specific remittance advice and the payer's current requirements before acting on any denial.

Work this denial faster

Denial trackers, corrected-claim checklists, and appeal templates.

Get denial trackers & appeal templates