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MA133 Remark Code: Claim Overlaps Inpatient Stay

MA133 means the claim overlaps an inpatient stay. The payer will only consider services rendered outside the inpatient stay, so rebill just those dates or services.

Quick facts

Code
MA133 (RARC MA133)
Status
Active In use since October 12, 2001.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): Services during the inpatient stay are not separately payable to you. The provider adjusts them; the patient is not billed.
Official description
Claim overlaps inpatient stay. Rebill only those services rendered outside the inpatient stay.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What MA133 means

MA133 tells you the dates on your claim overlap a patient’s inpatient stay on the payer’s records. During an inpatient stay, many services are covered by the hospital’s payment, so claims from other providers covering the same days may not be payable. The official instruction is to rebill only those services rendered outside the inpatient stay.

This remark is common on claims that span a date range, such as monthly supply claims, home health, or outpatient therapy.

Common causes

  • A claim spanning a date range included days when the patient was admitted.
  • An outpatient service was provided on the day of admission or discharge and overlaps under payer rules.
  • The patient was admitted without your knowledge, and billing continued as usual.
  • The inpatient stay dates on the hospital’s claim are wrong.

How to fix it

  1. Get the admission and discharge dates from the hospital or eligibility tools.
  2. Split the claim to remove dates within the inpatient stay.
  3. Rebill only the services outside the stay, as directed by the official text.
  4. Contact the hospital if the stay dates look incorrect.

How to prevent it

  • Check eligibility for recent inpatient stays before billing date-span claims.
  • Ask patients or caregivers about hospitalizations during the billing period.
  • See CO-18 duplicate and overlapping claims for related prevention tips.

Codes that may appear with MA133

  • CO-97 (The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated.): The benefit for these services is included in payment for another service, the inpatient stay.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim needs to be corrected before the services outside the stay can be processed.
  • N61 (Rebill services on separate claims.): Asks you to rebill services on separate claims.
  • MA80 (Informational notice.): An informational notice that a hospital was paid for all services in the encounter.
  • N332 (Missing/incomplete/invalid prior hospital discharge date.): A missing or invalid prior hospital discharge date.

MA133 FAQ

Why does an inpatient stay affect my claim?

Many services furnished to a hospital inpatient are covered by the hospital's inpatient payment. Some claims from other providers, such as outpatient facilities or suppliers, cannot be paid for dates within that stay.

How do I rebill correctly?

Remove the dates of service that fall within the inpatient stay and rebill only the services rendered before admission or after discharge.

What if the dates of the inpatient stay are wrong?

Confirm the admission and discharge dates with the hospital. If the payer's record is wrong, the hospital may need to correct its claim.