Skip to main content

N331 Remark Code: Physician Order Date Missing or Invalid

N331 means the date of the physician's order for the item or service was missing, incomplete, or invalid, so the payer could not confirm that a valid order existed before the service or delivery.

Quick facts

Code
N331 (RARC N331)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim was denied for a missing or invalid order date. The provider or supplier corrects it; the patient is not billed for this adjustment.
Official description
Missing/incomplete/invalid physician order date.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N331 means

For ordered services, payers want proof that a practitioner asked for the item or service before it was provided. The order date is how they check that sequence. N331 is returned when that date is absent, unreadable, or illogical (for example, later than the delivery date or in the future).

Suppliers of durable medical equipment and prosthetics see N331 most, but it can also show up on home health, infusion, and ordered diagnostic claims. It usually accompanies CARC 16; when the timing itself is the problem, CARC 174 may appear instead.

Common causes

  • The system captured the date the order was received or entered rather than the date it was signed.
  • A verbal order was followed by a written order, and the written order’s later date was reported.
  • A renewed or revised order exists, but the claim still points to an expired one.
  • The field was left empty because the order was stored as a scanned image with no data entry.
  • The date format was rejected by the payer’s edit.

How to fix it

  1. Open the signed order and identify the date the practitioner signed it. If there was a dispensing order followed by a detailed written order, check which date the payer’s policy expects.
  2. Confirm the order date is on or before the date of service or delivery, and that the order has not expired for recurring items.
  3. Correct the date on the claim in the field the payer designates and resubmit with frequency code 7 and the original claim number.
  4. If no valid order existed at the time of service, do not alter dates. Obtain what is required for future services and review whether the current claim is billable.

How to prevent it

Treat the order date as a required data element, keyed at intake from the signed document. Compare it with the delivery or start date before billing, and set reminders for orders that expire so renewals are signed ahead of the next service.

Codes that may appear with N331

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Required claim information is missing or invalid; N331 pinpoints the order date.
  • CO-174 (Service was not prescribed prior to delivery.): The service was not prescribed before delivery, which is what a late order date suggests.
  • CO-173 (Service/equipment was not prescribed by a physician.): The service or equipment was not prescribed by a physician, a related order problem.
  • N455 (Missing Physician Order.): Used when the physician order itself is missing, not just its date.
  • N456 (Incomplete/invalid Physician Order.): Used when the order was received but is incomplete or invalid.
  • N57 (Missing/incomplete/invalid prescribing date.): Addresses a missing or invalid prescribing date.

N331 FAQ

Which date is the 'order date'?

It is the date the ordering practitioner signed or issued the order for the item or service. It is not the date the order was received, scanned, or filled.

What if the order was dated after delivery?

Many payers require the order before delivery or before the service begins. A post-dated order may not be fixable by changing the date field; you may need to review whether the claim can be supported at all.

Do all claims need an order date?

No. It is mainly required for ordered services such as durable medical equipment, supplies, home health, and some therapy and diagnostic services. Payer rules vary.