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N326 Remark Code: Last X-Ray Date Missing

N326 means the date of the patient's last x-ray was missing, incomplete, or invalid. Payers that rely on imaging to support certain treatment, most commonly chiropractic care, need this date on the claim.

Quick facts

Code
N326 (RARC N326)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The provider must correct the x-ray date; the patient is not billed while the claim can be fixed.
Official description
Missing/incomplete/invalid last x-ray date.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N326 means

Some payers use x-ray findings to support the need for treatment, particularly manipulation for spinal subluxation. When the payer’s rules rely on imaging, it wants the date of the most recent x-ray on the claim so it can confirm the imaging is timely. N326 means that date wasn’t there or wasn’t valid.

It is usually paired with CARC 16. If the date is present but the payer judges the x-ray too old, remarks such as M1 may appear instead.

Common causes

  • No date reported. The practice documented subluxation from an x-ray, but the date never reached the claim.
  • Wrong qualifier. The date sits in box 15 under the qualifier for initial treatment or acute manifestation.
  • Future or illogical date. The x-ray date is after the date of service.
  • Outside imaging not tracked. The patient brought films from another facility and the date wasn’t recorded.
  • Payer location rules. The date was reported in a different box from the one the payer expects.

How to fix it

  1. Locate the x-ray report and note the date the images were taken.
  2. Check that it is on or before the date of service and fits the payer’s timing rules.
  3. Enter the date with the last x-ray qualifier in box 15, or where the payer instructs, and in the electronic equivalent.
  4. Keep the report available in case the payer requests documentation.
  5. Submit a corrected claim with frequency code 7.

How to prevent it

Record the x-ray date as a structured field in the initial evaluation, whether the imaging was done in-house or elsewhere, and map it to the claim automatically. Build a payer rule that holds chiropractic claims for payers that require the date when it’s missing. Our CARC and RARC guide shows how to confirm the fix by tracking this remark over time.

Codes that may appear with N326

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Missing or invalid information; N326 names the last x-ray date.
  • MA121 (Missing/incomplete/invalid x-ray date.): Another remark for a missing or invalid x-ray date.
  • M1 (X-ray not taken within the past 12 months or near enough to the start of treatment.): The x-ray wasn't taken within the required time or near enough to the start of treatment.
  • N306 (Missing/incomplete/invalid acute manifestation date.): The acute manifestation date is missing or invalid.
  • M122 (Missing/incomplete/invalid level of subluxation.): The level of subluxation is missing or invalid.

N326 FAQ

Where does the last x-ray date go on a CMS-1500?

Box 15 has a qualifier for the date of the last x-ray. Some payers give different instructions, such as reporting it in box 19, so check their guidance.

Is an x-ray always required for chiropractic claims?

No. Requirements differ by payer. Some accept other documentation of the condition; others want an x-ray within a certain time.

What if the x-ray was taken elsewhere?

Report its date and keep the report or images available in case the payer asks to review them.