CARC Code
166
Payer Responsibility Period Ended
The insurance company is denying this claim because the services were billed after their contract or responsibility to cover this plan had already ended. The payer is no longer obligated to process claims for this plan.
timely filingHow to resolve this denial
Identify subsequent payer and submit the claim to them
- 1
Pull the original claim and review the denial reason and any RARC codes
- 2
Research the payer's policy for CARC 166 to understand the basis for denial
- 3
Gather supporting documentation addressing the denial reason
- 4
Submit a formal appeal with the documentation within the plan's appeal window
- 5
Follow up on the appeal within 30 days and document all communication
▶✓ Pre-action checklist — verify before contacting the payer
Review the full remittance advice (ERA/EOB) for additional RARC codes that explain the denial.
Verify the claim was submitted with correct patient eligibility and benefit information.
Check if this denial applies to a specific line item or the entire claim.
▶More about CO-166 — stats, related codes, appeal template
35%
Recovery Rate
21-45 days
Avg. Resolution
Hard
Difficulty
Occasional
Frequency
Payer-Specific Notes
How major payers handle CARC 166 by specialty.
Blue Cross Blue Shield
BCBS requires appeal submission within 180 days for most plans.
Appeal Letter Template
Generic appeal template for CARC 166 denials.
We are submitting a formal appeal for claim [CLAIM_NUMBER] for patient [PATIENT_NAME], date of service [DOS]. This claim was denied/adjusted with CARC 166 indicating: "Services submitted after plan's responsibility ended. Liability with subsequent ." We have reviewed the claim and are providing the attached documentation to support reconsideration. [SUPPORTING_DOCUMENTATION]. Please reconsider payment per the terms of our contract.
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