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M10 Remark Code: DME Purchase Month Restriction

M10 means the payer only allows this equipment to be purchased in the first month of medical necessity or in the tenth month. A purchase billed at any other point was not paid as a purchase.

Quick facts

Code
M10 (RARC M10)
Status
Active In use since January 1, 1997.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The supplier absorbs the difference because the purchase was billed at a time the payer does not allow.
Official description
Equipment purchases are limited to the first or the tenth month of medical necessity.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M10 means

Some durable medical equipment can be rented or bought, but a purchase is only allowed at specific points. M10 says those points are the first month of medical necessity or the tenth month. If a supplier bills a purchase at month five, for example, the payer rejects it as a purchase and uses M10 to explain.

It is a Medicare DME remark reflecting the capped rental rules, and other payers may use the same wording for similar policies.

Common causes

  • The supplier billed a purchase midway through a rental.
  • The first month of need on the payer’s records differs from the supplier’s records, often because of a previous supplier.
  • The purchase modifier was used when the rental modifier was intended.
  • The patient asked to buy the item outside the allowed window and the supplier billed it anyway.

How to fix it

  1. Check the rental history and determine which month of medical necessity the claim falls in.
  2. If the purchase modifier was an error, submit a corrected claim with resubmission code 7, the right rental modifier, and the correct month.
  3. If the purchase was timed correctly by your records, send the payer the rental history and request reprocessing.
  4. If the timing was wrong, continue billing as a rental, and offer purchase at the permitted month where applicable.

How to prevent it

Tie DME modifiers to the rental month count in your billing system so a purchase can only be selected in eligible months. Check prior supplier history on transfers. See CARC and RARC denial analysis for reading these combinations.

Codes that may appear with M10

  • CO-96 (Non-covered charge(s).): The purchase is non-covered at the month it was billed.
  • CO-4 (The procedure code is inconsistent with the modifier used.): The modifier used, such as a new-purchase or rental modifier, does not fit the month of billing.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim did not include information needed to place the purchase in the right month.
  • M9 (Alert: This is the tenth rental month.): The tenth-month alert telling the supplier to offer the purchase option.
  • M7 (No rental payments after the item is purchased, returned or after the total of issued rental payments equals the purchase price.): No further rental once the item is purchased or fully paid.
  • N795 (Item must be resubmitted as a purchase.): The item must be resubmitted as a purchase.

M10 FAQ

Can I rebill the item as a rental instead?

Often, yes. If the item qualifies for rental, submit it with the correct rental modifier and month. Check the payer's DME policy for the item category.

Why does the tenth month matter?

Under the capped rental framework reflected in this remark, the tenth month was when the patient could convert to purchase.

Does M10 apply to inexpensive items?

Items the payer routinely allows as purchases generally follow different rules. M10 concerns equipment where purchase timing is restricted.