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M4 Remark Code: Last DME Installment Payment

M4 is an informational alert. It tells the supplier that this payment is the last monthly installment the payer will make for this durable medical equipment item.

Quick facts

Code
M4 (RARC M4)
Status
Active In use since January 1, 1997; last modified April 1, 2007.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): Any adjustment on the line follows normal contract rules. M4 itself only signals that installment payments are ending.
Official description
Alert: This is the last monthly installment payment for this durable medical equipment.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M4 means

Some durable medical equipment is paid in a series of monthly installments instead of one lump sum. M4 marks the payment that closes out that series. It is an alert, so it does not reduce or deny anything on its own. The dollar outcome is carried by the reason codes on the same line.

M4 is Medicare-oriented, but any payer paying DME in installments may use it.

What to do

  1. Post the payment normally and confirm the paid amount matches the expected installment.
  2. Update the rental record in your billing system so no further monthly claims are generated for this item.
  3. Check what comes next for the item. Depending on the payer’s rules, title may pass to the patient, and maintenance or servicing may be billed differently.
  4. Tell the patient if ownership or servicing arrangements change.

No correction or appeal is needed unless the payer ended installments earlier than your records show. In that case, compare your count of paid months against the remittances and contact the payer. Tracking installment counts in an ERA Analyzer report makes early cutoffs easy to spot.

Codes that may appear with M4

  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): A routine fee schedule reduction may appear on the same final installment line.
  • PR-2 (Coinsurance Amount): Patient coinsurance still applies to the last installment as it did to earlier ones.
  • N85 (Alert: This is the final installment payment.): A general alert that this is the final installment payment, not limited to DME.
  • N84 (Alert: Further installment payments are forthcoming.): The opposite message: more installment payments are still coming.
  • M7 (No rental payments after the item is purchased, returned or after the total of issued rental payments equals the purchase price.): Explains that rental payments stop once the item is purchased, returned, or fully paid.

M4 FAQ

Does M4 mean the claim was denied?

No. It is an alert attached to a payment. Check the CARC on the line to confirm the amount paid is what you expected.

What happens after the last installment?

Depending on the payment category, ownership may transfer to the patient, and the supplier may still have service or repair obligations. Check the payer's DME rules for that item.

Should I keep billing monthly after M4?

Generally no. Further monthly claims for the same item are likely to be denied because the payment cap has been reached.