CO 31: Patient Not Found
The payer cannot find this patient as a member.
Re-verify the member ID, name spelling and date of birth against the card, then resubmit.
See a finished review first
- No patient data
- No BAA
- No charge
- No pitch
What CO 31 means
CO: Contractual obligation. The provider absorbs it and cannot bill the patient.
So the balance cannot move to the patient. Either the appeal recovers it or the practice absorbs it. That makes the appeal decision the whole decision on this line.
Is It Worth Appealing?
Fix and resubmit. This is a correction, not an appeal. Appealing burns the deadline.
Why It Fires
In the order we see it.
A mistyped member ID, or a name that does not match the payer's record.
The patient gave an old card and has since changed plans.
How to Fix CO 31, Step by Step
Re-verify the member ID, name spelling and date of birth against the card, then resubmit.
- 1Step 1: Read the remark code. Find the remark code printed next to CO 31 on the 835 or EOB. It says what the payer wants back.
- 2Step 2: Find the cause. Match the denial to one of the 2 causes in Why It Fires above, and fix that one.
- 3Step 3: Do this. Re-verify the member ID, name spelling and date of birth against the card, then resubmit.
- 4Step 4: Attach the documentation. Current eligibility showing the correct member ID and plan.
The common mistake. Do not write this off as non-covered. It is almost always a data problem, and the claim pays once the identifiers match.
Free: the Denial Code Appeal Playbook. 53 codes on one sheet: appeal, fix and resubmit, or let it go, and what to attach. Get the playbook
CO 31 description
The payer cannot find this patient as a member.
The payer cannot find this patient as a member. So the balance cannot move to the patient. Either the appeal recovers it or the practice absorbs it. That makes the appeal decision the whole decision on this line.
This is our plain-English wording, not the official X12 text. X12 asserts copyright over the published descriptions, so we write our own and say what it means for the money rather than restating the code.
Where this comes from. This is our own reading of the code, not the payer's and not a copy of the standards text. We classify it from how these denials actually resolve. Where we are unsure, we say so rather than guessing.
Related Codes
CO 185
The rendering provider is not eligible to perform the service billed.
Read the CO 185 pageCO 242
The provider was out of network, or not the patient's assigned primary care provider.
Read the CO 242 pageCO 27
Coverage had ended on the date of service.
Read the CO 27 pageCO 26
Service fell before coverage started.
Read the CO 26 page
Your Questions Answered
What does CO 31 mean?
The payer cannot find this patient as a member. Contractual obligation. The provider absorbs it and cannot bill the patient.
Can you appeal CO 31?
Fix and resubmit. Re-verify the member ID, name spelling and date of birth against the card, then resubmit.
Why does CO 31 happen?
A mistyped member ID, or a name that does not match the payer's record. The patient gave an old card and has since changed plans.
What documentation wins a CO 31 appeal?
Current eligibility showing the correct member ID and plan.
How do I fix a CO 31 denial?
Step 1: Read the remark code. Find the remark code printed next to CO 31 on the 835 or EOB. It says what the payer wants back. Step 2: Find the cause. Match the denial to one cause: A mistyped member ID, or a name that does not match the payer's record. The patient gave an old card and has since changed plans. Step 3: Do this. Re-verify the member ID, name spelling and date of birth against the card, then resubmit. Step 4: Attach the documentation. Current eligibility showing the correct member ID and plan.
Most searched: CO 97 · CO 96 · OA 23 · PR 204 · CO 109 · CO 197 · CO 45 · CO 50
How Much of This Is Sitting in Your Write-Off Pile?
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