What does denial code CO-31 mean?

Patient cannot be identified as an insured. The payer can't match the patient to a member.

How do I fix a CO-31 denial?

Check the insurance card and verify eligibility. Correct the patient data and resubmit.

Pricing

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Claim adjustment reason code · Contractual obligation

CO-31
Patient cannot be identified as an insured

What CO-31 means

The payer can't match the patient to a member.

The CO group code means this amount is a contractual obligation: under most contracts you cannot bill it to the patient.

Common causes

Wrong member ID, name spelling or date of birth
Wrong payer

How to fix it

Check the insurance card and verify eligibility
Correct the patient data and resubmit

Check the remark code (RARC) that came with the denial and the payer's own policy, since rules vary by payer and plan. This is a plain-English summary written by GetMax; the official code text is published by X12 at x12.org/codes.

Prevent it next time

Most denials are caused before the claim is sent. See 12 ways to reduce claim denials, or let our denial management team work them for you.

Other codes

All denial codes →

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CO-31Patient cannot be identified as an insured