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N45 Remark Code: Paid at Authorized Amount

N45 means payment was based on the authorized amount. The payer priced the service according to what it approved in the authorization, such as a set number of units, visits, or a dollar amount, rather than the billed amount.

Code: N45 (RARC N45)
Status: Active In use since January 1, 2000.
Code set: Remittance Advice Remark Codes (RARC)
Group codes: CO (Contractual Obligation): The difference between the billed amount and the authorized amount is a contractual adjustment for the provider.
PR (Patient Responsibility): Patient cost-sharing calculated on the authorized amount.
Official description: Payment based on authorized amount.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What N45 means

Some services are paid according to what was approved in advance. When a payer authorizes, for example, a certain number of visits, units, or days, or a negotiated amount for a single-case agreement, it may cap payment at that authorization even if the claim reports more. N45 tells you the authorization, not the billed charge or fee schedule alone, determined the payment.

N45 frequently appears with CARC 45. When the billed units went beyond the approval, CARC 198 (authorization exceeded) may be on the same line.

Common causes

More units or visits were delivered than the authorization allowed.
A single-case agreement or negotiated rate set the payment amount.
The authorization approved a lower level of service than was billed.
The authorization covered a narrower date range than the services on the claim.

What to do

Pull the authorization and compare its approved units, dates, services, and amount to the claim.
Check the payer’s record to confirm the authorization was loaded as approved.
Request an update if the patient needed more care than was authorized. Ask whether the payer allows retroactive changes and reprocessing.
Dispute pricing errors if the payment is below the authorized amount or negotiated rate.
Post the difference as a contractual adjustment when the payment matches the approval.

How to prevent it

Track authorized units and dates against services delivered, and request extensions before the approval runs out. Make sure clinicians know the authorization limits at the start of each episode. See authorization and referral prevention for workflow ideas.

Codes that may appear with N45

CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge was reduced to an allowable, which N45 says came from the authorization.
CO-198 (Precertification/notification/authorization/pre-treatment exceeded.): The authorization was exceeded, so only the approved portion was paid.
CO-151 (Payment adjusted because the payer deems the information submitted does not support this many/frequency of services.): Units or frequency beyond what was approved were not supported.

N54 (Claim information is inconsistent with pre-certified/authorized services.): The claim information is inconsistent with the authorized services.
CO-284 (Precertification/authorization/notification/pre-treatment number may be valid but does not apply to the billed services.): The authorization number may be valid but does not apply to the billed services.
N27 (Missing/incomplete/invalid treatment number.): The treatment number is missing or invalid.

N45 FAQ

Is N45 a denial?

No. The service was paid, but the amount is tied to the authorization. It is only a problem if the authorization did not cover everything that was medically necessary.

Can I get paid for units beyond the authorization?

Some payers allow a request to extend or modify an authorization, sometimes retroactively. If they approve it, ask them to reprocess the claim.

What if the authorized amount was entered wrong?

Compare the approval letter with the payer's record. If the payer loaded the authorization incorrectly, ask for a correction and reprocessing.

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