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N118 Remark Code: Not Paid More Than Once Every 28 Days

N118 means the service is not paid if billed more than once every 28 days. The payer found another claim for the same service within the 28-day window, so the later one was denied.

Quick facts

Code
N118 (RARC N118)
Status
Active In use since July 30, 2002.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): A frequency denial treated as the provider's responsibility unless the patient accepted liability in advance.
  • PR (Patient Responsibility): Possible only if the patient was told in writing beforehand that the service would likely not be paid and agreed to pay.
Official description
This service is not paid if billed more than once every 28 days.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N118 means

N118 applies to services the payer expects no more than once in a four-week cycle. When a second claim arrives with a date of service inside 28 days of a paid one, the later claim is denied. It commonly pairs with CARC 119 or CARC 151.

The first question is always whether the dates are correct. The second is whether the two claims really describe the same service.

Common causes

  • The service was scheduled on a monthly calendar basis, which sometimes lands inside 28 days (for example, the 1st and the 28th of the next month).
  • A date of service was keyed incorrectly on one of the claims.
  • Two providers furnished the same service to the patient in the same window.
  • A service billed at the start of a cycle was also billed at the end of the prior cycle because of a date overlap.

How to fix it

  1. Pull both claims and compare the dates of service in CMS-1500 box 24A.
  2. If a date was wrong, submit a corrected claim with resubmission code 7 in box 22 and the original claim number.
  3. If both dates were correct, the later service falls inside the window. Check whether the payer allows exceptions for documented clinical need and appeal if so.
  4. If no exception applies, resolve the balance according to the group code and any signed patient notice.

How to prevent it

Schedule recurring services by interval (at least 28 days apart) rather than by calendar month. Your scheduling system can flag appointments that fall inside the window for services with this limit.

Codes that may appear with N118

  • PR-119 (Benefit maximum for this time period or occurrence has been reached.): The benefit maximum for this time period has been reached.
  • CO-151 (Payment adjusted because the payer deems the information submitted does not support this many/frequency of services.): The information submitted does not support this frequency of service.
  • N119 (This service is not paid if billed once every 28 days, and the patient has spent 5 or more consecutive days in any inpatient or Skilled /nursing…): A variant that also considers five or more consecutive inpatient or SNF days within the 28 days.
  • N117 (This service is paid only once in a patient's lifetime.): Limits the service to once in a lifetime.
  • M86 (Service denied because payment already made for same/similar procedure within set time frame.): Denies a service already paid for a same or similar procedure within a set time frame.

N118 FAQ

How are the 28 days counted?

Generally from the date of service of the earlier paid claim. Whether the window is 28 days inclusive or counts from the next day can vary, so confirm with the payer if the dates are close.

What if the dates of service were entered wrong?

Correct them in a replacement claim. A wrong date on either claim can make two services look closer together than they were.

Does N118 apply across providers?

It can. The payer looks at the patient's history, so a service billed by another provider may count against the window.