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N389 Remark Code: Duplicate Prescription Number

N389 means the prescription number on this claim was already submitted on another claim, so the payer treated this billing as a duplicate of an earlier fill.

Quick facts

Code
N389 (RARC N389)
Status
Active In use since August 1, 2007.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • OA (Other Adjustment): True duplicates are typically adjusted under OA, because the service was already handled on the earlier claim.
  • CO (Contractual Obligation): Some payers report the duplicate prescription under CO. Either way, the patient is not billed for the rejected duplicate.
Official description
Duplicate prescription number submitted.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N389 means

Payers check prescription numbers to catch the same fill billed twice. N389 says your claim used a prescription number the payer already has on file. It could be an actual duplicate, such as a resend of a claim already paid, or a legitimate new fill that looks like a repeat because distinguishing details are missing.

It normally pairs with CARC 18 or B13.

Common causes

  • Resubmission. A claim was sent again because no response had arrived, and the first one had been processed.
  • Missing refill indicator. A refill reused the Rx number without the fill or refill number that shows it’s new.
  • Corrections sent as new claims. An adjustment to quantity or code was billed as a fresh claim instead of a correction.
  • Split fills. A partial fill and its completion weren’t reported in the way the payer expects.
  • Multiple billing systems sending the same prescription.

How to resolve it

  1. Search for the earlier claim with the same prescription number and check its status and payment.
  2. If the earlier claim covers this fill, void your duplicate and close the account item.
  3. If this is a different fill, resubmit with the fill or refill number, dispensing date, and quantity that distinguish it.
  4. If the earlier claim was wrong, correct or reverse it rather than billing again. See duplicate claim denials for general practice.
  5. Contact the payer if you can’t find the earlier claim it matched.

How to prevent it

Turn off automatic resubmission for pharmacy and supply claims, check claim status before resending, and always include refill numbers. Use corrections or reversals for changes to a claim that was already processed.

Codes that may appear with N389

  • OA-18 (Exact duplicate claim/service (Use only with Group Code OA except where state workers' compensation regulations requires CO)): Exact duplicate claim or service.
  • CO-B13 (Previously paid.): Previously paid; payment may already have been made for this prescription.
  • N388 (Missing/incomplete/invalid prescription number.): Used when the prescription number is missing or invalid rather than repeated.
  • N378 (Missing/incomplete/invalid prescription quantity.): Covers a missing or invalid prescription quantity.
  • N380 (The original claim has been processed, submit a corrected claim.): Tells you to submit a corrected claim when the original was already processed.

N389 FAQ

Can a refill trigger N389?

Yes, if the refill is billed without a new fill or refill indicator the payer can use to tell it apart from the original fill.

What if I need to fix the original prescription claim?

Correct or reverse the original claim rather than sending a new one with the same prescription number.

Is N389 always a real duplicate?

No. It may be a separate fill that looks identical because a refill number, date, or quantity was missing. Check before writing it off.