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N411 Remark Code: Allowed Once Every 6 Months

N411 means the plan allows this service only once in a 6-month period, and the claim was denied or reduced because the patient already received it, or the payer believes they did, within that window.

Quick facts

Code
N411 (RARC N411)
Status
Active In use since August 1, 2007; last modified July 1, 2016.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The service exceeded a frequency limit under the payer's rules or your contract, and the provider writes off the amount.
  • PR (Patient Responsibility): The plan's benefit limit was reached, so the patient may owe the charge if they were informed beforehand and your contract allows it.
Official description
This service is allowed one time in a 6-month period.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N411 means

N411 is a frequency limit remark. The payer allows the billed service once in any six-month period, and its claim history shows an earlier instance close enough that this one falls inside the window. The remark explains CARC 119 or CARC 151 most often.

Six-month limits are frequently attached to routine or maintenance services. Which services carry the limit is set by the plan or the payer’s policy, so the same service can be unlimited for one patient and restricted for another.

How the six-month window trips claims

The most common problem is counting. A patient scheduled “every six months” can easily land a few days early. Whether that matters depends on the payer’s method:

  • counting forward six calendar months from the last date of service,
  • counting a fixed number of days, or
  • aligning to plan-defined periods.

Other causes include a service performed elsewhere that your office did not know about, a prior claim with the wrong date, or a duplicate line on the current claim.

How to fix it

  1. Ask the payer for the prior date of service it used. Compare it with your records.
  2. If the prior date was wrong (for example, a claim posted under the wrong date), get that claim corrected first, then ask for reprocessing of this one.
  3. If the current date or line was wrong, send a corrected claim with resubmission code 7.
  4. If the service was medically needed sooner, submit an appeal or exception request with the clinical reason.
  5. If the denial is valid, follow your contract and any advance notice rules before billing the patient.

How to prevent it

Check the last date of service before scheduling, and ask patients whether they had the service elsewhere recently. Build scheduling reminders that land safely after the six-month mark instead of on it. If you see N411 repeatedly for the same payer, ERA Analyzer can help you spot which services and payers keep hitting the limit.

Codes that may appear with N411

  • PR-119 (Benefit maximum for this time period or occurrence has been reached.): The benefit maximum for this time period has been reached; N411 states the limit is one service per six months.
  • 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.
  • CO-273 (Coverage/program guidelines were exceeded.): Coverage or program guidelines were exceeded, with N411 giving the specific frequency rule.
  • N412 (This service is allowed 2 times in a 12-month period.): A twice-per-12-months limit, which works differently from one every six months.
  • N415 (This service is allowed 1 time in an 18-month period.): A longer frequency window: one service in 18 months.
  • M86 (Service denied because payment already made for same/similar procedure within set time frame.): A general notice that payment was already made for the same or similar service within a set time frame.

N411 FAQ

Does six months mean 180 days?

Not always. Some payers count calendar months from the prior date of service, some count days, and a few use other methods. A service one day early can still deny, so check how the payer counts.

What if a different provider performed the earlier service?

It usually still counts. Frequency limits are typically tracked per patient, not per provider, so a service at another office can use up the benefit.

Can I get an exception for medical need?

Some plans allow more frequent services when the medical record supports it. Ask the payer about its exception or appeal process and include documentation of why the extra service was needed.