How do I fix or resolve code CO-31?

Verify the patient's member ID, name, and date of birth against the insurance card and a government-issued ID to ensure the claim was submitted with the correct demographic information. Run a 270/271 eligibility transaction with the exact member ID and name to confirm the patient is enrolled and identify any demographic discrepancies in the payer's system. If the member ID or name was entered incorrectly on the claim, correct the information in the practice management system and resubmit the claim with the accurate member ID and patient demographics. If the patient's name changed (e.g., marriage, divorce), contact the payer to update the enrollment record and resubmit once the payer confirms the update. If the patient is not enrolled in this payer's plan, determine the correct insurance and resubmit to the appropriate payer.

CO-31Denial CodeContractual Obligation

Code CO-31

Problem Description

Patient cannot be identified as our insured.

Root Cause

The patient cannot be identified as the payer's insured member. The payer's eligibility system cannot match the patient's name, member ID, date of birth, or other identifying information on the claim to an enrolled member in their database. This typically results from an incorrect member ID, a misspelled patient name, a name change not updated in the payer system, a transposed digit in the ID number, or the patient is not actually enrolled in this payer's plan. This is a demographic/eligibility mismatch, not a clinical denial.

Resolution Steps

1Verify the patient's member ID, name, and date of birth against the insurance card and a government-issued ID to ensure the claim was submitted with the correct demographic information.
2Run a 270/271 eligibility transaction with the exact member ID and name to confirm the patient is enrolled and identify any demographic discrepancies in the payer's system.
3If the member ID or name was entered incorrectly on the claim, correct the information in the practice management system and resubmit the claim with the accurate member ID and patient demographics.
4If the patient's name changed (e.g., marriage, divorce), contact the payer to update the enrollment record and resubmit once the payer confirms the update.
5If the patient is not enrolled in this payer's plan, determine the correct insurance and resubmit to the appropriate payer.

EHR Documentation Note

Claim denied CO-31 — patient not identified as insured; verified demographics against insurance card, corrected member ID or name, and resubmitted claim.

Preventative Action

Scan insurance cards at check-in and run real-time 270/271 eligibility checks to validate the member ID and patient demographics before claim submission.

Related Codes in Contractual Obligation

CO-4

The procedure code is inconsistent with the modifier used. Usage: Refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.

CO-5

The procedure code/type of bill is inconsistent with the place of service. Usage: Refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.

CO-16

Claim/service lacks information or has submission/billing error(s). Usage: Do not use this code for claims attachment(s)/other documentation. At least one Remark Code must be provided (may be comprised of either the NCPDP Reject Reason Code, or Remittance Advice Remark Code that is not an ALERT.) Refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.

CO-18

Exact duplicate claim/service (Use only with Group Code OA except where state workers' compensation regulations requires CO)

This directory provides reference information only and does not constitute official legal, medical, or financial billing advice. Always consult the payer's official remittance advice and current coding guidelines.