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N228 Remark Code: Incomplete or Invalid Consent Form

N228 means the payer received a required consent form, but it was incomplete or invalid. The best-known case is a Medicaid sterilization consent form, where federal rules set strict requirements for signatures, dates, and waiting periods.

Quick facts

Code
N228 (RARC N228)
Status
Active In use since August 1, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The service was denied because the consent did not meet requirements. The provider bears the loss; the patient should not be billed for a consent form defect.
Official description
Incomplete/invalid consent form.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N228 means

Certain services can only be paid when the patient’s informed consent has been documented on a specific form. N228 says the form was supplied but did not meet the requirements. The remark usually accompanies CARC 16 or CARC 252.

Sterilization under Medicaid is the standard example. Federal regulations prescribe the consent form and require, among other things, that the patient be of a minimum age, that a waiting period pass between signing and the procedure, and that the form be signed and dated by the right people. Payers review these forms closely because many defects cannot be cured.

Common causes

  • The waiting period between the patient’s signature and the procedure was not met.
  • Signatures or dates from the patient, the person obtaining consent, the interpreter, or the physician are missing.
  • The procedure date or type on the form does not match the claim.
  • An outdated version of the form was used.
  • Only one provider received a copy, and others billed without it.

What to do

  1. Review the form against the payer’s or state Medicaid program’s checklist to identify the specific defect.
  2. If the defect is clerical and your state permits correction, follow the approved process and resubmit.
  3. If the defect is substantive, such as a waiting period violation, the service is usually not payable; write it off per policy.
  4. Share the valid form with all providers on the case so each claim is supported.

How to prevent it

Have a single coordinator check sterilization consent forms before scheduling, confirm the waiting period, and send copies to the surgeon, anesthesia, and facility billing teams. Keep the current form version on file and retire old ones.

Codes that may appear with N228

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim or its support is missing or has invalid information; the consent form is the issue.
  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): Documentation, the consent form, was required.
  • CO-272 (Coverage/program guidelines were not met.): Program guidelines for the consent were not met.
  • N3 (Missing consent form.): The consent form was missing entirely.
  • N28 (Consent form requirements not fulfilled.): Consent form requirements were not fulfilled.
  • N399 (Incomplete/invalid elective consent form.): Incomplete or invalid elective consent form.

N228 FAQ

Which services require a consent form?

The most common is sterilization under Medicaid, which uses a federal consent form. Some payers and states also require consent forms for hysterectomies or other specific services.

Can a sterilization consent form be corrected?

Some clerical errors may be correctable according to state Medicaid guidance, but substantive requirements such as the waiting period and the patient's signature date generally cannot be fixed after the fact.

Do all providers on the case need the form?

Often yes. Surgeons, anesthesia providers, and facilities may each need a copy of the valid consent to be paid.