Skip to main content

M137 Remark Code: Part B Coinsurance Under a Demonstration

M137 means the coinsurance on the line is Medicare Part B coinsurance applied under a demonstration project or pilot program. It explains the patient's share rather than signalling a denial.

Quick facts

Code
M137 (RARC M137)
Status
Active In use since January 1, 1997; last modified November 1, 2012.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • PR (Patient Responsibility): The amount is patient responsibility as Part B coinsurance under the demonstration, collectible from the patient or a secondary payer.
  • CO (Contractual Obligation): Any separate contractual adjustment on the line follows the demonstration's payment rules and is not billed to the patient.
Official description
Part B coinsurance under a demonstration project or pilot program.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M137 means

Medicare tests new payment and care models through demonstrations and pilot programs. Under some of them, the way Part B coinsurance is calculated differs from standard rules. M137 tells you that the coinsurance on this line was calculated under such a demonstration or pilot.

It is an explanation of patient responsibility. The line was processed, and the coinsurance amount is what the patient, or their supplemental coverage, owes.

When you see it

  • The patient or your practice participates in a Medicare demonstration or pilot.
  • The service falls within the scope of the program.
  • Coinsurance is reported with CARC 2 and the PR group code.

What to do

  1. Post the coinsurance as patient responsibility.
  2. Forward to secondary coverage if the patient has a supplement or Medicaid that covers Part B coinsurance; crossovers may happen automatically.
  3. Bill the patient for any remaining balance according to your financial policy.
  4. Check the amount against the program’s rules if it seems unusual, and contact the contractor with questions.

Keeping it straight

  • Tag claims processed under demonstrations so staff recognise different cost-sharing patterns.
  • Explain to patients enrolled in demonstrations how their costs may differ.
  • Review cost-sharing trends with an ERA Analyzer to confirm the program is paying as expected.

Codes that may appear with M137

  • PR-2 (Coinsurance Amount): Coinsurance amount, with M137 explaining it was calculated under a demonstration.
  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge was reduced to the demonstration's allowed amount.
  • M116 (Processed under a demonstration project or program.): The demonstration project or program is ending.
  • M138 (Patient identified as a demonstration participant but the patient was not enrolled in the demonstration at the time services were rendered.): The patient was identified as a demonstration participant but was not enrolled on the date of service.
  • M139 (Denied services exceed the coverage limit for the demonstration.): Services exceeded the demonstration's coverage limit.

M137 FAQ

Is M137 a denial?

No. It describes how the patient's coinsurance was calculated under a demonstration or pilot.

Can I collect this amount from the patient?

Yes, as Part B coinsurance reported with the PR group code, or from a supplemental or secondary payer that covers it.

Why is the coinsurance different from usual?

Demonstrations and pilots may change how payment or cost-sharing is calculated. The project's terms determine the amount.