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N746 Remark Code: Incomplete Ambulance Report

N746 means the payer received an ambulance report for the transport but found it incomplete or invalid. It could not confirm the trip, its level of service, or its medical necessity from the documentation provided.

Quick facts

Code
N746 (RARC N746)
Status
Active In use since March 1, 2015.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The ambulance provider bears the adjustment while the report is deficient. The patient is not liable for it.
Official description
Incomplete/invalid Ambulance Report.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N746 means

With N746, the payer has the trip documentation but cannot rely on it. Ambulance reviewers look for a clear clinical picture: the patient’s condition, why other transportation was unsafe, what care was provided, and details that match the billed level of service and mileage. When any of that is missing or contradictory, the payer returns N746.

The remark is usually paired with CARC 251, and sometimes with CARC 50 or CARC 150 when the defect leaves medical necessity or level of service unsupported.

Common causes

  • The narrative describes the trip but not the patient’s condition requiring an ambulance.
  • The crew signatures or credentials are missing.
  • The level of service billed (for example, advanced versus basic life support) is not supported by the interventions documented.
  • Pick-up and destination, times, or loaded mileage in the report differ from the claim.
  • Pages or attachments, such as a certification statement, were not included.

How to fix it

  1. Read the payer’s review notes to identify the specific deficiency.
  2. Obtain the full report, including all pages and signatures.
  3. If the crew needs to clarify, use a dated addendum in line with your policy.
  4. If the claim itself was wrong, for example the level of service or mileage, correct it and resubmit with resubmission code 7.
  5. Resubmit the documentation through reconsideration or appeal.

How to prevent it

Train crews to document medical necessity explicitly, not just vitals. A pre-billing review that compares the report’s level of service and mileage to the claim catches most mismatches before the payer does.

Codes that may appear with N746

  • CO-251 (The attachment/other documentation that was received was incomplete or deficient.): The documentation received was incomplete or deficient.
  • CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): The report did not establish medical necessity for ambulance transport.
  • CO-150 (Payer deems the information submitted does not support this level of service.): The documentation does not support the level of service billed.
  • N745 (Missing Ambulance Report.): No ambulance report was received.
  • N157 (Transportation to/from this destination is not covered.): Transportation to or from this destination is not covered, a coverage issue rather than documentation.
  • N206 (The supporting documentation does not match the information sent on the claim.): The documentation does not match what was billed on the claim.

N746 FAQ

What makes an ambulance report incomplete?

Common gaps are missing crew signatures, no description of why the patient could not travel safely another way, missing vital signs or assessments, or times and mileage that do not match the claim.

Can the crew add details to the report later?

Only through a proper late entry or addendum that is dated and signed, following your agency's documentation policy. Do not alter the original.

What if the report is complete but the payer disagrees?

Request reconsideration or appeal and point to the specific parts of the report that support the transport and level of service.