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M18 Remark Code: Hospital or SNF Is Not the Home

M18 means the service or item is only approved for home use, and the patient was in a hospital or skilled nursing facility, neither of which counts as the patient's home. The line is not payable as billed.

Quick facts

Code
M18 (RARC M18)
Status
Active In use since January 1, 1997; last modified June 30, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The supplier or provider absorbs the denied amount. The facility stay usually covers such items.
  • PR (Patient Responsibility): The patient may be responsible only in narrow cases, such as a valid advance notice for an item not covered anywhere.
Official description
Certain services may be approved for home use. Neither a hospital nor a Skilled Nursing Facility (SNF) is considered to be a patient's home.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M18 means

Several Medicare benefits, especially durable medical equipment, are defined around the patient’s home. A hospital or skilled nursing facility cannot be the home for these purposes, because the facility is expected to supply what the patient needs during the stay. M18 says a home-use item or service was billed while the patient was in one of those facilities.

Most often it appears alongside a place of service reason code, such as CARC 5 or 58.

Common causes

  • Equipment was delivered and billed while the patient was still admitted.
  • The patient was in a skilled nursing facility stay and the supplier was unaware.
  • The claim listed a facility place of service code instead of the home.
  • The date of service was set to the delivery date rather than the discharge date.

How to fix it

  1. Confirm where the patient was on the date of service, and whether a facility stay overlapped.
  2. If the setting or date was coded wrongly, submit a corrected claim with resubmission code 7 and the right place of service (box 24B) and date (box 24A).
  3. If the patient was truly in the facility, the item should come from the facility. Bill the facility if you supplied it under arrangement.
  4. If the patient has since gone home and still needs the item, bill for a date on or after discharge.

How to prevent it

Ask about current or recent admissions at order intake and hold delivery billing until discharge. Pre-submission Claims Validator checks can flag facility place of service codes on home-use items.

Codes that may appear with M18

  • CO-5 (The procedure code/type of bill is inconsistent with the place of service.): The procedure code or bill type is inconsistent with the place of service.
  • CO-58 (Treatment was deemed by the payer to have been rendered in an inappropriate or invalid place of service.): Treatment was deemed rendered in an inappropriate or invalid place of service.
  • CO-96 (Non-covered charge(s).): The item is non-covered in the setting where the patient was.
  • M21 (Missing/incomplete/invalid place of residence for this service/item provided in a home.): The place of residence for a home service is missing or invalid.
  • M2 (Not paid separately when the patient is an inpatient.): Services during an inpatient stay are not paid separately.
  • N107 (Services furnished to Skilled Nursing Facility (SNF) inpatients must be billed on the inpatient claim.): Services to SNF inpatients must be billed on the inpatient claim.

M18 FAQ

Which items does M18 usually affect?

Durable medical equipment and supplies covered under a home-use benefit, such as equipment delivered while the patient is still admitted.

Can equipment be delivered before discharge?

Some payers allow delivery shortly before discharge for fitting or training, with billing dated for the discharge day. Check the payer's DME rules.

What place of service should a home claim show?

The place of service in box 24B should reflect the patient's actual residence, such as home or a qualifying residential setting.