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N500 Remark Code: Medical-Legal Report Incomplete

N500 means the carrier received a medical-legal report but found it incomplete or invalid. The report may not address the disputed issues, may lack required attestations or signatures, or may not meet the jurisdiction's content rules. Submit a corrected report and rebill.

Quick facts

Code
N500 (RARC N500)
Status
Active In use since July 1, 2008.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The evaluator must correct the report. The adjustment is not the injured person's responsibility.
Official description
Incomplete/invalid Medical Legal Report.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N500 means

The carrier has the medical-legal report, but it will not pay for the evaluation based on it as written. Because these reports decide contested questions in workers’ compensation and other injury cases, states often spell out what they must contain. N500 means the reviewer found something missing or out of line with those requirements.

  • Unanswered issues. The report skips a question the parties or adjuster put to the evaluator.
  • Missing attestations. Some states require specific signed declarations, for example on who performed which parts of the evaluation.
  • Records review gaps. The report does not list or discuss the records reviewed when the jurisdiction requires it.
  • Billing support. The report does not document the time, complexity, or elements needed for the level of evaluation billed.
  • Administrative errors. Wrong claim number, missing date of injury, or unsigned pages.

What to do

  1. Read the carrier’s explanation and identify each deficiency it cites.
  2. Decide whether the objection is valid under the jurisdiction’s rules.
  3. If it is, prepare a corrected or supplemental report addressing each point, signed by the evaluator, and serve it as the state requires.
  4. Rebill or request a second review of the bill within the jurisdiction’s timelines.
  5. If it is not, use the state’s bill review and dispute process, citing the rule the report satisfies.

How to prevent it

Build a report template for each jurisdiction with every required attestation and section, and check the billed evaluation level against the report’s documented elements before billing. Medical-legal disputes tend to be slow, so avoiding the first rejection matters.

Codes that may appear with N500

  • CO-251 (The attachment/other documentation that was received was incomplete or deficient.): The report was received but was deficient.
  • CO-P13 (Payment reduced or denied based on workers' compensation jurisdictional regulations or payment policies, use only if no other code is applicable.): Payment was reduced or denied under workers' compensation jurisdictional rules.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Missing or invalid information prevented adjudication.
  • N499 (Missing Medical Legal Report.): No medical-legal report was received.
  • N498 (Incomplete/invalid Medical Permanent Impairment or Disability Report.): An impairment or disability report is incomplete or invalid.
  • N591 (Payment based on an Independent Medical Examination (IME) or Utilization Review (UR).): Payment was based on an independent medical exam or utilization review.

N500 FAQ

What makes a medical-legal report incomplete?

Common issues are not addressing every disputed question, missing a required attestation or signature, omitting the review of records the evaluator relied on, or lacking information needed to support the billed evaluation level.

Can a carrier reduce payment instead of denying it?

Yes. In some jurisdictions the carrier may pay at a lower level if the report does not support the evaluation level billed. Dispute rules vary by state.

Does fixing the report restart any deadlines?

That depends on the jurisdiction. Check the state's rules on supplemental and corrected reports before resubmitting.