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N540 Remark Code: Interrupted Stay Payment Adjustment

N540 means payment was adjusted based on the payer's interrupted stay policy. When a patient leaves a facility and returns within a short period defined by the policy, the payer treats both periods as one stay and pays accordingly rather than as two separate admissions.

Code: N540 (RARC N540)
Status: Active In use since November 1, 2010.
Code set: Remittance Advice Remark Codes (RARC)
Group codes: CO (Contractual Obligation): The adjustment follows the payer's payment policy for stays. It is not billable to the patient.
Official description: Payment adjusted based on the interrupted stay policy.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What N540 means

Facilities paid per stay, rather than per day, can be affected when a patient leaves briefly and comes back. Interrupted stay policies prevent a short break from generating two full stay payments. If the patient returns within the policy’s window, the payer treats the two periods as one continuous stay.

N540 tells you the payer applied that policy to your claim. Payment was recalculated for a single stay, and one claim may have been reduced, denied, or merged with the other.

Common causes

The facility billed two separate admissions when the return fell within the interruption window.
Discharge and readmission dates were entered in a way that made the gap look shorter than it was.
The patient left for a short acute-hospital stay and the return was treated as a new admission.

How to fix it

Confirm the dates of discharge and return, and count the gap the way the payer’s policy counts it.
If the policy applies, follow the payer’s billing instructions for interrupted stays, typically a single claim that reports the interruption.
If the gap exceeded the window, appeal or request correction with documentation of the actual dates.
Check both claims. A combined stay may require canceling one claim and adjusting the other.
Resubmit as a corrected or replacement claim according to the payer’s institutional billing rules.

How to prevent it

Have registration flag any patient returning within a short period of discharge, and route those accounts to billing staff who know the interrupted stay rules for your facility type. Checking the gap before billing avoids a cancel-and-rebill cycle.

Codes that may appear with N540

CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge exceeds the allowed payment after the stays were combined.
CO-97 (The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated.): The second period's payment is included in the payment for the combined stay.
OA-18 (Exact duplicate claim/service (Use only with Group Code OA except where state workers' compensation regulations requires CO)): Some payers deny a separately billed return as a duplicate of the combined stay.

N47 (Claim conflicts with another inpatient stay.): The claim conflicts with another inpatient stay.
CO-249 (This claim has been identified as a readmission. (Use only with Group Code CO)): The claim was identified as a readmission, a different policy from interrupted stays.
CO-A6 (Prior hospitalization or 30 day transfer requirement not met.): Prior hospitalization or 30 day transfer requirement not met.

N540 FAQ

What is an interrupted stay?

A stay where the patient is discharged, or leaves, and then returns to the same facility within a short window set by the payer's policy. Medicare, for example, has interrupted stay rules for inpatient rehabilitation, long-term care hospital, and inpatient psychiatric facility stays.

How should an interrupted stay be billed?

Payers generally want a single claim covering the whole stay, with the interruption reported using the codes or dates their billing instructions specify. Check the payer's manual for the setting.

How is this different from a readmission?

Readmission policies typically apply to returns to an acute hospital within a longer period and may reduce or deny payment. Interrupted stay rules combine short breaks in a post-acute or specialty stay into one stay.

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