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N673 Remark Code: Outpatient Per Diem or Factor Pricing

N673 means the payer calculated an outpatient claim using an outpatient per diem, an outpatient factor such as a percentage of charges, a fee schedule amount, or a mix of these. It describes how the payment was set, not a denial.

Quick facts

Code
N673 (RARC N673)
Status
Active In use since July 15, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The difference between billed charges and the calculated outpatient amount is a contractual or fee schedule write-off.
  • PR (Patient Responsibility): Any patient cost-sharing on the outpatient allowed amount appears under PR.
Official description
Reimbursement has been calculated based on an outpatient per diem or an outpatient factor and/or fee schedule amount.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N673 means

Facility outpatient claims are priced in many ways. Some payers pay a flat per diem for each day of outpatient service, some apply a factor, typically a percentage of charges, and some pay particular services from a fee schedule, with the rest handled another way. N673 is a single remark that covers any of these, alone or combined.

You’ll see it on hospital outpatient and ambulatory facility claims, especially from Medicaid programs, commercial contracts, and state workers’ compensation hospital schedules that use these methods.

Why the amount can vary

Because N673 bundles several methods, the most common confusion is simply not knowing which one was used on each line. Payment can also be off because:

  • The payer counted the wrong number of outpatient days for a per diem.
  • The factor or percentage applied doesn’t match the contract.
  • Services with a fee schedule amount were paid by factor instead, or the reverse.
  • Revenue codes or procedure codes on the lines didn’t map to the expected category.

What to do

  1. Identify the methodology in your contract or the jurisdiction’s rules for this claim type.
  2. Break the payment down by line and match each line to the method that should apply.
  3. Post the adjustment where the calculation matches.
  4. Correct your coding if a revenue code or procedure code routed a line to the wrong method, and send a replacement claim under the payer’s institutional billing rules.
  5. Request reprocessing if the payer applied the wrong per diem, factor, or schedule amount.

How to prevent it

Model each payer’s outpatient methodology in your contract management system so expected payments can be calculated for every claim. Review the mapping of revenue and procedure codes whenever your charge master changes, since a single mapping error can misprice many claims.

Codes that may appear with N673

  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge exceeded the outpatient allowed amount.
  • N676 (Service does not qualify for payment under the Outpatient Facility Fee Schedule.): The service doesn't qualify for payment under the outpatient facility fee schedule at all.
  • N671 (Payment based on a jurisdiction cost-charge ratio.): Payment based on a jurisdiction cost-to-charge ratio.
  • N638 (Reimbursement has been made according to the home health fee schedule.): Pricing under a home health fee schedule.
  • N647 (Adjusted based on diagnosis-related group (DRG).): Inpatient payment based on a diagnosis-related group.

N673 FAQ

What is an outpatient factor?

Usually a percentage or multiplier applied to charges or to a base rate, as defined in the contract or state rule. The exact meaning depends on the payer's methodology.

Why would one claim use more than one method?

Many outpatient methodologies pay some services from a fee schedule and the remaining charges by a per diem or percentage. N673 covers that combination.

How do I know which method was used?

Check the line-level allowed amounts and your contract or the applicable state schedule. If it is still unclear, ask the payer for its pricing breakdown.