M2 remark code

Remittance advice remark code M2. Remark codes add detail to the reason code on the same claim line.

Patient was an inpatient at the time

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What M2 means

The service was furnished while the patient was an inpatient, so it is not paid as a separate line outside the facility claim.

The payer is saying the patient was registered as an inpatient on the date of service, and this service falls under the facility's inpatient payment instead of being paid to you on its own.

It usually travels with a reason code about bundling or inclusion in another payment, such as 97. Check the admission and discharge dates before assuming the denial is right.

Common causes

• The date of service falls between the patient's admission and discharge dates at a hospital or similar facility.
• A supplier or outside lab billed separately for something the inpatient facility is expected to furnish.
• The patient's inpatient dates on the payer's file are wrong or overlap an outpatient visit.

What to do next

1. Confirm the admission and discharge dates with the facility or the patient's record.
2. If the service is part of the inpatient stay, arrange payment through the facility under your agreement with it.
3. If the dates on file are wrong, ask the payer to correct them and then request reprocessing.

Related codes

• 97 (reason code) Service included in another payment
• MA133 (remark code) Dates fall inside an inpatient stay