CARC 166 Active

PR-166: Payer's Responsibility Ended Before Service Date

TL;DR

Patient responsibility — review the adjustment and determine if the patient truly owes this amount.

Action
Review & Decide
Who Pays
Patient
Appeal
No
Patient Impact
Direct Financial
Disclaimer
This content is for informational purposes only and does not constitute professional billing advice. Always verify information against your payer contracts and current coding guidelines. Consult a certified billing specialist for specific claim issues.

What Does PR-166 Mean?

With PR (Patient Responsibility), the CARC 166 adjustment for payer's responsibility ended before service date shifts the financial impact to the patient. Before billing the patient, verify that the denial reason is valid. if the underlying issue can be corrected, resubmit the claim first to potentially eliminate the patient's liability.

CARC 166 indicates payer's responsibility ended before service date. The payer determined that the service or a portion of it does not meet coverage criteria under the patient's current plan benefits or the applicable coverage rules.

Common scenarios that trigger this adjustment include: the patient's insurance plan with this payer ended before the date the service was rendered, so the payer is no longer responsible for processing claims; The employer group switched insurance carriers or terminated the plan, and the service was rendered after the transition date; The payer retroactively terminated the patient's coverage, and claims for services rendered during the period that is now uncovered are being denied. The group code paired with CARC 166 determines who bears the financial responsibility — CO places it on the provider as a contractual obligation, OA indicates a coordination of benefits or other payer adjustment, PR shifts it to the patient.

How to Resolve

  1. Review the adjustment Examine the PR-166 adjustment and any RARC codes to understand the basis for the patient responsibility.
  2. Verify the adjustment is correct Confirm the PR designation and amount are appropriate based on the patient's plan benefits.
  3. Appeal if incorrect If the adjustment appears incorrect, file an appeal with supporting documentation.
  4. Collect from the patient if valid If the adjustment is confirmed correct, generate a patient statement and follow standard collection procedures.
Do Not Appeal This Code

Payer's Responsibility Ended Before Service Date grouped under PR places the financial responsibility on the patient. The specific reason depends on the context of this adjustment — review any accompanying RARC codes for detail. Because this represents a placement of responsibility rather than a coverage denial, an appeal isn't the right action; verify the placement is correct before billing the patient.

How to Prevent PR-166

Also Filed As

The same CARC 166 may appear with different Group Codes:

CO-166 OA-166

Related Denial Codes

PR-13 — Date of Death Precedes Date of Service PR-14 — Date of Birth Follows Date of Service PR-19 — Workers' Compensation Claim PR-20 — Liability Carrier Responsible PR-21 — No-Fault Carrier Responsible

Sources

  1. https://www.mdclarity.com/denial-code-carcs
  2. https://x12.org/codes/claim-adjustment-reason-codes
  3. https://portal.ct.gov/-/media/ohs/health-it-advisory-council/apcd-advisory-group/data-submission-guide-workgroup/meeting-materials/6-30-22/carc-codes_final.pdf
  4. https://medicaid-documents.dhhs.utah.gov/Documents/pdfs/ClaimDenialCodes.pdf
  5. Codes maintained by X12. Visit x12.org for official definitions.