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N457 Remark Code: Missing Diagnostic Report

N457 means the diagnostic report is missing. The payer needs the written report of a diagnostic test or study, such as the interpretation of an imaging exam, and did not receive it with the claim or in response to its request.

Quick facts

Code
N457 (RARC N457)
Status
Active In use since July 1, 2008.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim is held or denied until the report is received. The provider supplies it; the patient is not billed.
Official description
Missing Diagnostic Report.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N457 means

Diagnostic services produce two things: the test itself and a written report of what it showed. N457 says the payer needs that report and does not have it. It appears on claims for interpretations, where the report is the billed work product, and on claims for treatment where the payer wants to see the diagnostic findings that supported it.

Look for N457 with CARC 252 or CARC 226.

Typical situations

  • Professional interpretation billed for imaging, cardiac testing, or other studies, and the payer wants proof of the interpretation.
  • Treatment justified by test results, such as a procedure or therapy that the payer approves only when specific findings exist.
  • Workers’ compensation claims where the carrier needs test findings to link treatment to the injury.
  • Medical review of high-cost or frequently tested services.

What to do

  1. Identify the specific study the payer is asking about, including date and type.
  2. Obtain the final, signed report. If another provider performed or read the test, request a copy from them.
  3. Make sure the report matches the claim: same patient, date, and study.
  4. Submit it through the payer’s attachment process, labeled with the claim number, and track receipt.
  5. Ask for reprocessing once the payer confirms receipt.

How to prevent it

For services where a report routinely supports payment, attach it at submission. Hold interpretation claims until the final report is signed, so you are not billing a service that exists only in draft. Keep outside reports indexed in the patient record so billing staff can find them quickly.

Codes that may appear with N457

  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): Documentation is required; N457 identifies the diagnostic report.
  • CO-226 (Information requested from the Billing/Rendering Provider was not provided or not provided timely or was insufficient/incomplete.): Requested information was not provided or was insufficient.
  • CO-B12 (Services not documented in patient's medical records.): Services not documented in the patient's medical records, which can apply to an interpretation billed without a report.
  • N458 (Incomplete/invalid Diagnostic Report.): The diagnostic report was received but was incomplete or invalid.
  • N395 (Missing laboratory report.): A laboratory report is missing.
  • N467 (Missing Tests and Analysis Report.): A tests and analysis report is missing.

N457 FAQ

Why does the payer need the report for a test it already knows was done?

For interpretation services, the written report is the service. For follow-up treatment, the report shows the findings that justify it.

What if the report is at another facility?

Request a copy from the facility or reading provider. If you billed the interpretation, the report should be in your own records.

Is a preliminary report enough?

Usually not. Payers generally expect the final, signed report.