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M6 Remark Code: Supplier Must Furnish for Item Lifetime

M6 is an alert to the supplier. It says you must keep furnishing and servicing this item whenever the patient needs it, for the rest of the equipment's reasonable useful lifetime, even though rental payments may have stopped.

Quick facts

Code
M6 (RARC M6)
Status
Active In use since January 1, 1997; last modified March 1, 2009.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The adjustment, often a zero-pay rental month, is the supplier's responsibility. M6 reminds you that service obligations continue anyway.
Official description
Alert: You must furnish and service this item for any period of medical need for the remainder of the reasonable useful lifetime of the equipment.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M6 means

M6 is a Medicare-style DME alert. After a rental period ends, the payer may stop paying the monthly rental amount, but the supplier does not get to walk away. M6 states that the supplier must continue to furnish the equipment and keep it working for any period the patient medically needs it, until the item reaches its reasonable useful lifetime.

It most often arrives on oxygen equipment and other rental items after the payment cap, frequently next to a zero-pay line.

What to do

  1. Read the paired reason code. If the line was paid or adjusted as expected, no billing action is needed.
  2. Keep the item in service. Continue delivery, maintenance, and repairs as the patient needs them.
  3. Flag the patient account so staff do not remove equipment or stop service because payments ended.
  4. Review which servicing charges are separately billable under the payer’s rules, and bill those under the correct codes.

If you believe the rental period had not actually ended, compare your paid months to the payer’s records and contact the payer. Otherwise M6 is simply a reminder to keep supporting the patient.

Codes that may appear with M6

  • PR-119 (Benefit maximum for this time period or occurrence has been reached.): The rental payment maximum has been reached for the item.
  • CO-35 (Lifetime benefit maximum has been reached.): A lifetime or period benefit maximum applies to the equipment.
  • M5 (Monthly rental payments can continue until the earlier of the 15th month from the first rental month, or the month when the equipment is no longer…): Explains the rental payment limit itself, rather than the supplier's continuing obligation.
  • M4 (Alert: This is the last monthly installment payment for this durable medical equipment.): Marks the final installment payment for the equipment.
  • N371 (Alert: title of this equipment must be transferred to the patient.): Alerts the supplier that title to the equipment must pass to the patient.

M6 FAQ

Is M6 a denial?

Not in itself. It is an alert about the supplier's obligations. Any denial or reduction on the line is explained by the reason code.

Which equipment does M6 usually involve?

It is typically seen on Medicare oxygen and capped rental equipment, where the supplier keeps the item available after rental payments end.

Can the supplier bill for maintenance after the cap?

Some maintenance and servicing may be billable under separate rules, but the regular rental payment does not continue. Check the payer's DME policy for the item category.