21Denial Code (CARC)Active
Effective 01/01/1995 · Updated 09/30/2007

Denial Code 21 - No-Fault Carrier Liability

Code 21 indicates that the claim is denied because the injury or illness is the responsibility of a no-fault insurance carrier. This means the payer believes another insurance policy should cover the costs, not them.

Who Pays: Group Code Liability

Code 21 means a no-fault carrier — usually auto PIP or med-pay coverage — owns this injury claim, not the health plan. It typically arrives as OA-21 or PR-21. The right move is to bill the no-fault carrier, not to write the balance off and not to bill the patient yet. If no-fault benefits are denied or exhausted, resubmit to the health plan with the no-fault carrier’s determination attached; whatever remains then follows normal plan liability.

Why Claims Get Code 21

  • The patient's primary insurance is a no-fault policy, such as auto insurance, but the claim was sent to a health insurer.
  • The provider did not indicate the no-fault insurance information on the claim.
  • The submitted claim lacked necessary accident information or details.
  • The payer's coordination of benefits records show no-fault insurance as primary.
  • A mistake in the insurance information, leading to incorrect payer billing.

How to Fix & Resubmit

  1. Verify the patient's insurance information to ensure that the no-fault carrier details are correct.
  2. Contact the patient to confirm the no-fault insurance policy and obtain any missing information.
  3. Update the claim with the correct no-fault insurance details and resubmit it to the appropriate payer.
  4. If the no-fault insurance information is not available, contact the payer to clarify the coordination of benefits.
  5. Ensure all accident-related details are included in the claim before resubmission.

Corrected Claim or Appeal?

A corrected claim is appropriate if the no-fault insurance information was missing or incorrect. An appeal may be necessary if there's evidence that the payer's coordination of benefits is wrong or outdated.

Preventing Future 21 Denials

  • Collect comprehensive insurance information from patients during registration, including no-fault policies.
  • Train staff to recognize when no-fault insurance may be primary, especially for accident-related visits.
  • Review and confirm coordination of benefits before claim submission to avoid misrouting.
  • Ensure all accident details are accurately documented and included in claims.