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M25 Remark Code: Level of Service Not Supported

M25 means the payer decided the documentation does not support the level of service billed. It explains how to request a review and warns that amounts collected from the patient beyond cost-sharing may have to be refunded.

Code: M25 (RARC M25)
Status: Active In use since January 1, 1997; last modified November 1, 2010.
Code set: Remittance Advice Remark Codes (RARC)
Group codes: CO (Contractual Obligation): The reduction is the provider's responsibility. Extra amounts already collected from the patient may need to be refunded.
PR (Patient Responsibility): Applies only if the patient agreed in writing, in advance, to pay for the higher level of service.
Official description: The information furnished does not substantiate the need for this level of service. If you believe the service should have been fully covered as billed, or if you did not know and could not reasonably have been expected to know that we would not pay for this level of service, or if you notified the patient in writing in advance that we would not pay for this level of service and he/she agreed in writing to pay, ask us to review your claim within 120 days of the date of this notice. If you do not request an appeal, we will, upon application from the patient, reimburse him/her for the amount you have collected from him/her in excess of any deductible and coinsurance amounts. We will recover the reimbursement from you as an overpayment.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What M25 means

M25 is a Medicare-rooted remark with real consequences. The payer reviewed the information on the claim, and possibly the records, and concluded that the level of service billed was more than the documentation supports. The line may be downcoded or reduced.

The remark also sets out your options. You can ask for a review if you believe the service was covered as billed, if you did not know and could not have known the payer would not pay this level, or if the patient agreed in writing in advance to pay. If you take no action, the patient can ask the payer to reimburse them for what you collected beyond deductible and coinsurance, and the payer will recover it from you.

Common causes

Visit levels selected without documentation to support the complexity or time.
Services billed at a higher intensity than the notes describe.
Missing records, so the reviewer could not see the supporting details.
Templates that produce the same high level for every encounter.

How to fix it

Pull the record and compare it to the level billed and the payer’s documentation guidelines.
If the record supports the level, request a redetermination within the deadline on your notice, with the full documentation.
If it does not, accept the adjustment. Refund the patient any amount collected above their cost-sharing for the lower level.
If an advance written agreement exists, include it with your review request.

How to prevent it

Audit visit and service levels against documentation regularly, and train providers on what each level requires. Track M25 frequency by provider using an ERA Analyzer to find patterns early. For the broader documentation picture, see CARC and RARC denial analysis.

Codes that may appear with M25

CO-150 (Payer deems the information submitted does not support this level of service.): The information submitted does not support this level of service.
CO-151 (Payment adjusted because the payer deems the information submitted does not support this many/frequency of services.): The information submitted does not support this many or this frequency of services.
CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): The higher level of service was not deemed medically necessary.

M26 (The information furnished does not substantiate the need for this level of service.): Same finding, but focused on the mandatory refund to the patient within 30 days.
N355 (Alert: The law permits exceptions to the refund requirement in two cases: - If you did not know, and could not have reasonably been expected to…): Describes the exceptions to the refund requirement.
N10 (Adjustment based on the findings of a review organization/professional consult/manual adjudication/medical advisor/dental advisor/peer review.): Adjustment based on a review organization or medical advisor's findings.

M25 FAQ

Does M25 mean the whole service was denied?

Not necessarily. The payer may have paid at a lower level of service and denied only the difference.

How long do I have to ask for a review?

The remark references a 120-day window from the date of the notice, which matches the Medicare redetermination deadline. Confirm the date on your remittance.

What happens if I do not appeal?

Under the remark, the payer may reimburse the patient for amounts you collected above deductible and coinsurance, and then recover that money from you as an overpayment.

Can I charge the patient the difference?

Only if you gave written advance notice that the payer might not pay for this level and the patient agreed in writing.

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