CO-150 Denial Code: Level of Service Not Supported

The official definition

“Payer deems the information submitted does not support this level of service”

That is the verbatim definition of CARC 150 from the X12 Claim Adjustment Reason Code set, the standardized codes every insurer uses on EOBs and remittance advices. The letters in front of the number are the group code. CO: Contractual Obligation: an adjustment between the provider and the insurer. An in-network provider should not bill you for CO amounts.

What it means in plain English

The insurer agrees you needed care. They just don't think you needed this much. A Level 4 office visit they think should have been a Level 3, an inpatient stay they think should have been outpatient. Very often the care was appropriate and the documentation submitted with the claim simply didn't show it.

What to check on your EOB

• What was billed vs. what was paid. The EOB shows the insurer downgraded rather than denied outright.
• Whether the visit involved complexity the billed level reflects: multiple problems addressed, medication changes, extended time.

What to do next

1. Ask the provider to submit the complete medical record, not just the claim summary: detailed exam findings, decision-making complexity, time documentation.
2. Have the physician write a letter explaining the complexity of the case and why the billed level was appropriate.
3. File the appeal with the full documentation attached.

Who's responsible

Provider, with the physician's documentation. Most denials carry a clear owner. Knowing whether the fix belongs to you, your doctor, or the billing office is half the battle. If it's the provider's error, you should not be paying for it.

Want the fundamentals first? Start with how to read an EOB and the 7 most common billing errors. This page is general information about standardized denial codes, not legal or medical advice.