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N399 Remark Code: Incomplete Elective Consent Form

N399 means the payer received the consent form for an elective procedure, but it was incomplete or invalid, for example missing signatures or dates, the wrong form version, or signed outside required time limits.

Quick facts

Code
N399 (RARC N399)
Status
Active In use since August 1, 2007.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim is denied because the consent requirement wasn't satisfied. The provider absorbs the adjustment if the defect can't be corrected; the patient is not billed.
Official description
Incomplete/invalid elective consent form.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N399 means

N399 comes after the payer reviewed the consent form. It’s not that the form was missing; it’s that the form didn’t meet the payer’s requirements. Consent rules for certain elective procedures can be strict about who signs, when, and on which version of the form.

Expect it with CARC 251 or CARC 252.

Typical defects

Reviewers commonly reject consent forms for:

  1. A missing patient, witness, interpreter, or physician signature
  2. Missing or illegible dates
  3. Signing too soon before the procedure, or too long before it, for programs with timing rules
  4. An outdated or unofficial form version
  5. Blank required fields, such as the procedure name or the patient’s age or identifiers
  6. Details that don’t match the claim (different procedure, provider, or date)

Which defects can be fixed

Some problems are administrative, such as a missing physician signature after the fact or an unclear copy, and payers may accept a corrected or clearer copy. Others go to the heart of consent: the patient’s own signature, a required waiting period, or the patient’s eligibility to consent. Those usually can’t be corrected after the procedure. Knowing which type you have saves time.

How to fix it

  1. Get the payer’s specific reason for rejecting the form.
  2. Check the original form against the requirements.
  3. For correctable defects, obtain a corrected or legible copy following the payer’s rules and resubmit it with the claim number.
  4. For defects that can’t be corrected, consider whether an appeal is realistic and don’t bill the patient where program rules prohibit it.
  5. Share the result with the other providers billing for the same procedure.

How to prevent it

Have a trained staff member check every consent form against the payer’s checklist before the procedure is scheduled, not after. Store the current form version centrally so outdated copies aren’t used.

Codes that may appear with N399

  • CO-251 (The attachment/other documentation that was received was incomplete or deficient.): The attachment received was incomplete or deficient.
  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): A valid attachment is still needed to adjudicate the claim.
  • N398 (Missing elective consent form.): Used when no elective consent form was received at all.
  • N228 (Incomplete/invalid consent form.): Covers an incomplete or invalid consent form in general.
  • N28 (Consent form requirements not fulfilled.): Says consent form requirements were not fulfilled.

N399 FAQ

Can I fix a missing signature?

Sometimes. A missing provider signature or an unfilled administrative field may be correctable per the payer's rules. A patient signature or date that fails a required waiting period generally can't be corrected afterward.

What if we used an outdated form?

Some payers reject expired form versions. Ask whether the old version is acceptable for the date of service before assuming the claim is lost.

Should I resubmit the claim or just the form?

Usually just the corrected form, following the payer's attachment or reconsideration process. Confirm with the payer.