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Denial Code Decoder

Claim adjustment reason code · CARC 181

Procedure code not valid for the service date

The payer's code tables show the procedure code you billed wasn't valid on the day the service was done, so it can't pay the line.

Next step: Fix and resubmit

Common causes

  • The CPT or HCPCS code was retired, or hadn't taken effect yet, on that date, since code sets change on a regular schedule.
  • A claim for an older date of service was coded with a code from a newer code set.
  • The code was picked or typed wrongly.

How to fix it

  1. Look up the code in the CPT or HCPCS code set that was effective on the date of service.
  2. Choose the valid code that describes what was done. Never change the date of service to make a code fit.
  3. Update your charge master and coding software so retired codes can't be selected.
  4. Send a corrected claim.

How long you have to appeal

Appeal and timely filing windows by payer
PayerAppeal windowTimely filingSource
Medicare (fee-for-service)120 days from the date you receive the initial determination, to request a redetermination from the Medicare Administrative Contractor (MAC). Medicare presumes you received it 5 days after the date on the notice.1 calendar year (12 months) after the date of service. Limited exceptions exist, for example when a Medicare contractor's error caused the delay.CMS: first level of appeal (redetermination)42 CFR 424.44: time limits for filing claimschecked 2026-10-05
Medicare AdvantageNon-contracted providers: 65 calendar days from the date of the plan's denial notice (remittance advice) to request a reconsideration, and you must submit a waiver of liability that holds the patient harmless. Contracted providers: use the dispute process in your plan contract.CMS counts the 65 days from the remittance notice date, which is the 60-day filing period plus the 5 days Medicare presumes it takes you to receive the notice. Some plans' own provider materials quote 60 days, so filing inside 60 days is the safer course.Contracted providers: set by your plan contract. Non-contracted providers: CMS's appeals guidance gives no single filing limit, so check the plan's provider manual. For private fee-for-service plans, CMS applies Original Medicare's limit of 1 calendar year after the date of service.CMS: Parts C & D appeals guidance (non-contract provider payment requests, section 40.12.1)42 CFR 422.582: standard reconsideration filing time and presumed receiptCMS Medicare Managed Care Manual, chapter 16a, section 120: PFFS timely filingUnitedHealthcare: non-contracted provider dispute and appeal rights (Medicare Advantage)checked 2026-10-05
Medicaid (state and managed care)Varies by state and by Medicaid managed-care plan. Check your state Medicaid provider manual or the plan's provider manual.Examples of the spread: New York Medicaid expects claims within 90 days of the date of service; Nevada Medicaid allows 30 calendar days from the remittance advice date to appeal a denied claim; Texas HHSC allows 120 calendar days for its medical and utilization-review appeals.Federal rules require state Medicaid agencies to set a claim filing deadline of no more than 12 months from the date of service. Your state or plan may set a shorter one.42 CFR 447.45: timely claims paymentNew York Medicaid (eMedNY): general billing guidelines, professionalNevada Medicaid: tip sheet for claims appealsTexas HHSC: provider appeals, medical and utilization reviewchecked 2026-10-05
Aetna (commercial)180 calendar days from the initial claim decision to file a level 1 reconsideration. A level 2 appeal is due within 60 calendar days of the reconsideration decision. Some states set a different window for fully insured plans; Aetna lists them on its exceptions page.Set by your Aetna agreement. Aetna's provider manual does not publish one national claim-filing limit, and some states set their own (for example, its New York supplement says 120 days).Aetna: disputes and appeals overviewAetna: state exceptions for the dispute and appeal processAetna: provider manual (claim disputes must meet contractual time frames)Aetna: provider manual state supplement (New York claim submission period)checked 2026-10-05
Cigna (commercial)180 calendar days from the date of the initial payment or denial notice. If the appeal is about a payment Cigna adjusted, 180 calendar days from the last payment adjustment.Participating providers: 90 days after the date of service. Out-of-network providers: 180 days after the date of service. Exceptions apply, such as a longer period required by law or allowed in your provider agreement.Cigna: appeals and disputes for health care providersCigna: submit and pay claims (filing limits)checked 2026-10-05
UnitedHealthcare (commercial)12 months from the date of the original claim EOB or remittance advice, counting the claim reconsideration step and the appeal step together (not 12 months for each). Your agreement or state law can change this.Set by your UnitedHealthcare agreement and by state requirements. The Administrative Guide gives no single national limit, so check your Participation Agreement.UnitedHealthcare: 2026 Care Provider Administrative Guide (claim reconsideration and appeals, timely filing)UnitedHealthcare: pre- and post-service appeals and reconsiderationschecked 2026-10-05
Blue Cross Blue Shield (local plans)Varies by local Blue plan; there is no single national window. Check the provider manual and contract for the Blue plan you bill. For out-of-area (BlueCard) patients that is usually your local plan, not the plan on the member's card.BCBS is an association of independent, locally operated companies, each with its own provider manual.Varies by local Blue plan.BCBSA: local Blue Cross and Blue Shield companiesHighmark: BlueCard program FAQ (claims for out-of-area members go to your local Blue plan)checked 2026-10-05

Your payer contract may set a different window.

Seen as CO-181, PR-181, OA-181 or PI-181?

The prefix tells you who is responsible for the amount:

What the group prefix on a denial code means
PrefixMeansBill the patient? (Medicare)
COContractual obligation. The provider absorbs the amount. Under Medicare, the patient cannot be billed for it.No
PRPatient responsibility. The patient owes the amount and it may be billed to the patient.Yes
OAOther adjustment. An adjustment that assigns no financial liability to either the provider or the patient.No
PIPayer-initiated reduction. A payer-initiated reduction. X12 allows it, but Medicare has never used it because it doesn't say who is financially liable.Depends

Sources: X12 Claim Adjustment Group Codes, checked 2026-10-04; CMS Transmittal 470 (CR 3685, Feb 2005): group and reason code use, checked 2026-10-04

Related codes

Sources

This explanation is written in our own words. Check the official list for the exact code text.