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N581 Remark Code: Coverage Investigation Pending

N581 means the payer has not decided the claim because an investigation into coverage eligibility is still pending. Payment is on hold until the insurer determines whether the policy covers the patient and the loss.

Quick facts

Code
N581 (RARC N581)
Status
Active In use since July 15, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • OA (Other Adjustment): The amount is pending, not denied. It is neither a write-off nor a patient balance yet.
  • CO (Contractual Obligation): Some payers report the held amount under CO. Treat it as pending unless the payer states otherwise.
Official description
Investigation of coverage eligibility is pending.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N581 means

Before a property and casualty insurer pays medical bills, it may investigate whether the policy actually covers this person and this event, for example whether the policy was active, who was driving, or whether the injury happened as reported. N581 says that investigation is still open. The claim is on hold, not denied.

The matching CARC is typically P8 (claim under investigation), and some payers use CARC 133 (pending further review).

Why it happens

  • The insurer is verifying facts about the loss, such as the date, location, and circumstances.
  • It is confirming the patient is an eligible injured person under the policy.
  • It is waiting on statements or documents from the policyholder, the patient, or others involved.

What to do

  1. Record the pending status and set a follow-up date. Don’t write the balance off.
  2. Contact the adjuster for the reason, what is outstanding, and the expected decision date.
  3. Ask the patient to respond promptly to any insurer requests, since patient cooperation often drives these delays.
  4. Protect other filing deadlines. If you may need to bill health insurance, understand its timely filing rules now. See timely filing denials.
  5. Avoid duplicate submissions. Resending the same bill can trigger duplicate denials. See duplicate claim denials.

How to prevent delays

Collect the claim number, adjuster contact, and a clear description of the accident at the first visit, and send documentation with the first bill so the carrier is not waiting on you.

Codes that may appear with N581

  • CO-P8 (Claim is under investigation.): The claim is under investigation, a property and casualty code that matches N581.
  • OA-133 (The disposition of this service line is pending further review. (Use only with Group Code OA).): The disposition of the service is pending further review.
  • N611 (Claim in litigation.): The claim is in litigation; contact the insurer.
  • N582 (Benefits suspended pending the patient's cooperation.): Benefits are suspended until the patient cooperates.
  • N675 (Additional information is required from the injured party.): Additional information is required from the injured party.

N581 FAQ

How long can the investigation take?

It varies by carrier and state. Some jurisdictions set time limits for P&C insurers to accept or deny a claim. Ask the adjuster for an expected timeline.

Should I bill the patient's health plan while waiting?

Depending on state rules and the plans involved, you may be able to bill health insurance and let the plans sort out who is primary. Check both payers' coordination rules first.

Do I need to resubmit?

Usually not. The payer will issue a decision once the investigation ends. Follow up rather than sending duplicate claims.