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N178 Remark Code: Missing Pre-Op Images or Visual Fields

N178 means the payer needed pre-operative images, such as clinical photographs, or visual field test results to support the service, and they were not received. It commonly appears on eyelid and brow surgery claims where the payer must distinguish functional from cosmetic procedures.

Quick facts

Code
N178 (RARC N178)
Status
Active In use since February 28, 2003; last modified November 1, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The service was denied or held for lack of required documentation. The provider must supply it; the patient should not be billed while it can be corrected.
  • PR (Patient Responsibility): Rare. If the procedure is ultimately judged cosmetic, the plan may assign responsibility to the patient, depending on notices and plan terms.
Official description
Missing pre-operative images/visual field results.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N178 means

For some procedures, a payer cannot tell whether surgery was medically necessary or cosmetic without seeing the patient’s condition beforehand. N178 says those pre-operative images or visual field results were expected and did not arrive. The remark usually accompanies CARC 252 (attachment required) or CARC 16 (missing information).

Oculoplastic surgery is the most familiar setting. Payer policies for eyelid procedures often ask for frontal photographs showing lid position relative to the pupil and automated visual field testing with and without the lids taped. Exact requirements vary by plan, so the medical policy is the authority.

Common causes

  • Photos and fields exist in the chart but were not attached to the claim.
  • The claim was submitted electronically without an attachment control number, so the payer could not match the paperwork.
  • Visual fields were done but only one condition (untaped) was recorded.
  • The surgeon’s office and the facility each assumed the other would send the images.

How to fix it

  1. Pull the pre-operative photographs and visual field reports from the chart, confirming they are dated before surgery and labelled with the patient’s name.
  2. Send them through the payer’s attachment channel, referencing the claim number or attachment control number.
  3. If the payer requires a new claim submission, file a corrected claim with resubmission code 7 in box 22 and note the attachment in box 19 if requested.
  4. If the documentation was sent and ignored, call the payer to confirm receipt before resubmitting.

How to prevent it

Add a pre-surgery checklist for procedures with a cosmetic counterpart: photos taken, fields performed under each required condition, results scanned into the chart, and prior authorization obtained where required. Attach the documentation when the claim is first created rather than waiting for a request.

Codes that may appear with N178

  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): An attachment is required to adjudicate the claim; N178 names the images or visual fields as that attachment.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim lacks information needed to adjudicate; the pre-operative documentation is what is missing.
  • CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): Without the images or visual fields, the payer may decide it cannot establish medical necessity.
  • N244 (Incomplete/Invalid pre-operative images/visual field results.): The companion code when images or visual fields were sent but were incomplete or invalid.
  • N40 (Missing radiology film(s)/image(s).): Missing radiology films or images, a different type of imaging documentation.
  • M127 (Missing patient medical record for this service.): Missing patient medical record for the service in general.

N178 FAQ

What kinds of procedures trigger N178?

Most often upper eyelid and brow procedures, where payers want photos and visual field testing to show the condition obstructs vision. Some payers apply it to other procedures with a cosmetic counterpart.

How do I send the images?

Use the payer's attachment method, which may be an electronic attachment linked to the claim, a portal upload, or fax with a cover sheet referencing the claim. Box 19 or the 837 attachment reference can link the paperwork.

Can I take the photos after the surgery?

No. The purpose is to document the pre-operative condition. If none were taken beforehand, discuss options with the payer, but expect an appeal to be difficult.