CO 107: Related Service Not Billed
The related service this one depends on was not on the claim.
Bill the qualifying service, or resubmit both lines on one claim so the payer can see the relationship.
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What CO 107 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.
An add-on code billed without its primary procedure.
The related service went out on a separate claim and the payer could not link them.
How to Fix CO 107, Step by Step
Bill the qualifying service, or resubmit both lines on one claim so the payer can see the relationship.
- 1Step 1: Read the remark code. Find the remark code printed next to CO 107 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. Bill the qualifying service, or resubmit both lines on one claim so the payer can see the relationship.
- 4Step 4: Attach the documentation. Both services on one claim, or the claim number of the primary procedure.
The common mistake. Do not appeal an add-on code on its own. Without the primary on the claim the payer has nothing to attach it to.
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 107 description
The related service this one depends on was not on the claim.
The related service this one depends on was not on the claim. 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 236
This procedure and another one billed the same day cannot be billed together under NCCI.
Read the CO 236 pageCO 97
The payer says this is already paid inside another service.
Read the CO 97 pageCO 234
This procedure is not paid separately.
Read the CO 234 pageCO B15
A required prior service was not billed or not covered.
Read the CO B15 page
Your Questions Answered
What does CO 107 mean?
The related service this one depends on was not on the claim. Contractual obligation. The provider absorbs it and cannot bill the patient.
Can you appeal CO 107?
Fix and resubmit. Bill the qualifying service, or resubmit both lines on one claim so the payer can see the relationship.
Why does CO 107 happen?
An add-on code billed without its primary procedure. The related service went out on a separate claim and the payer could not link them.
What documentation wins a CO 107 appeal?
Both services on one claim, or the claim number of the primary procedure.
How do I fix a CO 107 denial?
Step 1: Read the remark code. Find the remark code printed next to CO 107 on the 835 or EOB. It says what the payer wants back. Step 2: Find the cause. Match the denial to one cause: An add-on code billed without its primary procedure. The related service went out on a separate claim and the payer could not link them. Step 3: Do this. Bill the qualifying service, or resubmit both lines on one claim so the payer can see the relationship. Step 4: Attach the documentation. Both services on one claim, or the claim number of the primary procedure.
Most searched: CO 97 · CO 96 · OA 23 · PR 204 · CO 109 · CO 197 · CO 45 · CO 50
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