CO 11: Diagnosis Mismatch
The diagnosis does not match the procedure billed.
Recode from the chart and resubmit.
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- No patient data
- No BAA
- No charge
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What CO 11 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.
The diagnosis does not support the procedure billed.
How to Fix CO 11, Step by Step
Recode from the chart and resubmit.
- 1Step 1: Read the remark code. Find the remark code printed next to CO 11 on the 835 or EOB. It says what the payer wants back. The usual ones are MA63.
- 2Step 2: Find the cause. Match the denial to one of the cause in Why It Fires above, and fix that one.
- 3Step 3: Do this. Recode from the chart and resubmit.
- 4Step 4: Attach the documentation. A recode from what the record actually documents.
The common mistake. Do not appeal without rereading the note. If the coding was wrong, correcting it is faster than arguing.
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 11 description
The diagnosis does not match the procedure billed.
The diagnosis does not match the procedure billed. 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.
The Remark Code Beside It
The adjustment code says the claim was reduced. The remark code printed next to it says why, and it is the one that tells you what to send back.
| Remark | What it means |
|---|---|
| MA63 | The principal diagnosis is missing, not coded to full specificity, or not valid on the date of service. |
Related Codes
CO 5
The procedure does not match the place of service billed.
Read the CO 5 pageCO 4
The procedure code and the modifier do not agree.
Read the CO 4 pageCO 59
Reduced under multiple-procedure rules.
Read the CO 59 pageCO 150
The payer says the records do not support the level of service billed.
Read the CO 150 page
Your Questions Answered
What does CO 11 mean?
The diagnosis does not match the procedure billed. Contractual obligation. The provider absorbs it and cannot bill the patient.
Can you appeal CO 11?
Fix and resubmit. Recode from the chart and resubmit.
Why does CO 11 happen?
The diagnosis does not support the procedure billed.
What documentation wins a CO 11 appeal?
A recode from what the record actually documents.
How do I fix a CO 11 denial?
Step 1: Read the remark code. Find the remark code printed next to CO 11 on the 835 or EOB. It says what the payer wants back. Step 2: Find the cause. Match the denial to one cause: The diagnosis does not support the procedure billed. Step 3: Do this. Recode from the chart and resubmit. Step 4: Attach the documentation. A recode from what the record actually documents.
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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