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N686 Remark Code: Required Questionnaire Not Usable

N686 means the payer needs a questionnaire to finish its payment decision, and the questionnaire was missing, incomplete, or invalid. Common examples are accident, other-insurance, and injury questionnaires that the patient or provider must complete.

Code: N686 (RARC N686)
Status: Active In use since November 1, 2013.
Code set: Remittance Advice Remark Codes (RARC)
Group codes: CO (Contractual Obligation): The claim is held or denied until the questionnaire is completed. When the provider's form is missing, the provider is responsible for resolving it.
PR (Patient Responsibility): When the questionnaire was sent to the patient and not returned, the payer may assign the claim to the patient. Encourage the patient to complete it before billing them.
Official description: Missing/incomplete/Invalid questionnaire needed to complete payment determination.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What N686 means

Payers use questionnaires to collect facts that don’t fit on a claim form. An accident questionnaire asks how an injury happened and whether another party could be liable. A coordination of benefits questionnaire asks whether the member has other coverage. Other forms ask about student status, pre-existing conditions, or details of a particular service.

N686 says the payer’s determination depends on one of these forms, and it doesn’t have a usable one. The form may never have been returned, may be missing answers or a signature, or may contain answers that contradict each other.

Common causes

The member ignored or never received a mailed questionnaire.
The form was returned without a signature or with key sections blank.
An injury diagnosis triggered an accident questionnaire that nobody expected.
The member’s answers conflicted with information on the claim.
The provider didn’t respond to a questionnaire addressed to the office.

How to fix it

Find out which questionnaire the payer needs and who it was sent to.
Contact the patient if the form is theirs, explain why it matters, and give them a way to complete it by phone, portal, or mail.
Complete provider questionnaires promptly with accurate, documented information.
Follow up with the payer once it’s submitted and ask for the claim to be reprocessed.
Check other coverage if the questionnaire reveals another payer. See eligibility and COB denials.

How to prevent it

Ask about accidents and other insurance at every registration, and remind patients to answer payer mail about their claims. For injury-related visits, tell patients to expect an accident questionnaire and to return it quickly.

Codes that may appear with N686

CO-227 (Information requested from the patient/insured/responsible party was not provided or was insufficient/incomplete.): Information requested from the patient, insured, or responsible party wasn't provided or was insufficient.
CO-226 (Information requested from the Billing/Rendering Provider was not provided or not provided timely or was insufficient/incomplete.): Information requested from the billing or rendering provider wasn't provided or was insufficient.
CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim lacks information needed for adjudication.

N375 (Missing/incomplete/invalid questionnaire/information required to determine dependent eligibility.): A questionnaire specifically about dependent eligibility is missing or invalid.
N675 (Additional information is required from the injured party.): Additional information is required from the injured party on an injury claim.
OA-22 (This care may be covered by another payer per coordination of benefits.): The care may be covered by another payer per coordination of benefits.

N686 FAQ

Who completes the questionnaire?

It depends on the form. Accident and other-insurance questionnaires usually go to the member, while some clinical or service questionnaires go to the provider. The payer's letter says who it asked.

Can the office complete it for the patient?

Staff can help the patient understand the form, but the patient should provide and attest to their own answers. Don't fill in facts you can't verify.

Will the claim reprocess automatically?

Some payers reprocess held claims once the questionnaire is received; others need a request or resubmission. Ask the payer.

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