N329 remark code

Remittance advice remark code N329. Remark codes add detail to the reason code on the same claim line.

Patient birth date problem

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What N329 means

The patient's date of birth on the claim is missing, incomplete or does not match the payer's records.

Payers use the date of birth together with the member ID and name to identify the patient. N329 means the birth date did not line up, so the payer could not confirm the person on the claim is its member.

It adds detail to a missing information or patient identification reason code, usually 16 or 31, and is usually fixed by a corrected claim.

Common causes

• A typo in the date of birth during registration.
• The subscriber's birth date was entered for a dependent patient, or the reverse.
• The payer has an outdated or wrong birth date for the member.

What to do next

1. Compare the date of birth on the claim with the patient's ID and the eligibility response.
2. Correct the registration and submit a corrected claim.
3. If the payer's record is wrong, ask the patient to update it with the plan.
4. Check that patient and subscriber details are in the correct loops.

Related codes

• N382 (remark code) Patient ID missing or invalid
• 16 (reason code) Missing information or billing error
• MA36 (remark code) Missing or invalid patient name