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M129 Remark Code: X-Ray Availability Indicator Missing

M129 means the claim was missing, or had an incomplete or invalid, indicator showing whether an x-ray is available for the payer to review. It is typically seen on chiropractic claims where imaging supports the subluxation.

Quick facts

Code
M129 (RARC M129)
Status
Active In use since January 1, 1997; last modified June 30, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The service was not paid due to missing information. The provider corrects and resubmits; the patient is not billed.
Official description
Missing/incomplete/invalid indicator of x-ray availability for review.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M129 means

On chiropractic claims, payers may want to know whether imaging exists to support the diagnosis of subluxation and whether it can be reviewed on request. Some payers ask for this as a specific indicator on the claim. M129 tells you the indicator was not there, or was not in a valid form.

M129 does not mean the payer rejected your x-ray or even that one was required. It means a claim-level data element was missing.

Common causes

  • Chiropractic claims submitted without the payer-specific x-ray availability field or narrative.
  • Software that does not populate the field from the patient record.
  • An indicator value that does not match the payer’s accepted codes.
  • Inconsistency between the indicator and the x-ray date reported.

How to fix it

  1. Check the payer’s chiropractic claim requirements for the indicator and its accepted values.
  2. Confirm from the record whether an x-ray exists and where it is stored.
  3. Add the indicator (and x-ray date if required) and resubmit, using frequency code 7 if the claim was adjudicated.

How to prevent it

  • Configure chiropractic claim templates to require the indicator and x-ray date.
  • Record imaging information at the initial visit so it carries forward to every claim.
  • Check chiropractic claims with a Claims Validator before release.

Codes that may appear with M129

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim lacks information, identified by M129 as the x-ray availability indicator.
  • MA121 (Missing/incomplete/invalid x-ray date.): The x-ray date was missing or invalid.
  • M1 (X-ray not taken within the past 12 months or near enough to the start of treatment.): The x-ray was not taken recently enough relative to treatment.
  • M111 (We do not pay for chiropractic manipulative treatment when the patient refuses to have an x-ray taken.): Manipulation denied because the patient refused an x-ray.

M129 FAQ

Do I need to send the x-ray itself?

Not usually. M129 is about indicating whether an x-ray exists and is available for review if requested.

What if no x-ray was taken?

Indicate that, as the payer requires. Some payers, including Medicare, accept physical examination findings to demonstrate subluxation.

Where is the indicator reported?

In the claim fields or narrative the payer specifies for chiropractic claims. Check the payer's instructions.