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CO-213 Denial Code: Physician Self-Referral Violation

CO-213 means the payer denied the service for non-compliance with physician self-referral prohibition legislation, such as the federal Stark Law, or with the payer's own self-referral policy. It usually signals a financial relationship between the referring physician and the billing entity.

Quick facts

Code
CO-213 (CARC 213)
Status
Active In use since January 27, 2008.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider is responsible. A self-referral denial generally cannot be billed to the patient.
Official description
Non-compliance with the physician self referral prohibition legislation or payer policy.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-213 means

CARC 213 says the claim reflects non-compliance with the physician self-referral prohibition legislation or payer policy. In Medicare, the main law is the federal physician self-referral law, commonly called the Stark Law. It restricts physicians from referring certain designated health services to entities with which they, or an immediate family member, have a financial relationship, unless an exception applies. Many states have their own self-referral rules, and commercial payers may have policies of their own.

When a payer uses CARC 213, it has concluded that the referring physician and the billing entity have a relationship that makes the service non-payable. That is a compliance finding, not a data-entry problem, and it deserves a different response from ordinary denials.

Common causes

  • Ownership or investment interest by the referring physician in the entity furnishing the service, such as imaging, lab, or therapy.
  • Compensation arrangements that do not meet an applicable exception.
  • In-office ancillary services that do not satisfy the conditions of that exception, such as location or supervision requirements.
  • Referring provider data on the claim in box 17/17b that matches an owner or employee in the payer’s records.
  • Incorrect referring provider entered on the claim, making an unrelated service look self-referred.

How to fix it

  1. Confirm the referring provider on the claim is accurate. If it was a data-entry error, correct it and submit a corrected claim (frequency code 7).
  2. If the referral data was accurate, stop and involve your compliance officer and healthcare counsel before any appeal or resubmission.
  3. Review the financial relationship and whether a documented exception applies.
  4. Respond to the payer only after counsel advises on the approach; an appeal may be appropriate if an exception applies and you can document it.
  5. Do not bill the patient for the denied service.
  6. Consider the wider exposure. A self-referral issue on one claim may affect other claims under the same arrangement; counsel can advise on review and any refund obligations.

How to prevent it

  • Keep a current list of physician owners, investors, and compensation arrangements for every entity that bills designated services.
  • Have counsel review referral arrangements before launching ancillary services.
  • Train schedulers and billers to flag referrals from owners or related parties for compliance review.
  • Verify the referring provider field against the actual order before submission.
  • Audit periodically to confirm arrangements still meet the exception they rely on.

This page is general information, not legal advice. Self-referral rules are complex and fact-specific.

Remark codes that may appear with CO-213

  • N381 (Alert: Consult our contractual agreement for restrictions/billing/payment information related to these charges.): Points to contract terms on referrals and ownership.
  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Points to plan policies that restrict self-referred services.
  • N286 (Missing/incomplete/invalid referring provider primary identifier.): The referring provider identifier on the claim is part of what the payer is questioning.
  • CO-170 (Payment is denied when performed/billed by this type of provider.): Denied because of the provider type performing or billing the service, not because of a referral relationship.
  • CO-242 (Services not provided by network/primary care providers.): Denied because the service was not provided by a network or primary care provider.
  • CO-B7 (This provider was not certified/eligible to be paid for this procedure/service on this date of service.): Denied because the provider was not certified or eligible for this service on this date.

CO-213 FAQ

Does CO-213 mean I violated the Stark Law?

It means the payer believes the claim does not comply with self-referral law or its policy. Whether an actual violation occurred is a legal question. Talk to healthcare counsel before responding.

Can I just resubmit with a different referring provider?

Only if the original referring provider was entered in error. Changing the referring provider to get paid, when that is not who actually referred the patient, would be inaccurate billing.

Can I bill the patient?

No. CO-213 is a provider-liability denial, and self-referral rules generally prohibit collecting for the prohibited service.