CO-150 denial code
Documentation does not support this level of service
How to fix it
Review the note against the level billed. Appeal only where the documentation genuinely supports it.
How to prevent it
Address this through documentation templates rather than through coding policy; the record is what failed.
In practice
An established patient visit is billed at a high level based on a complex medication adjustment and review of outside records. The claim is downcoded and returns CO-150: documentation does not support this level of service.
The work was done. The note records the assessment and the plan but does not show the data reviewed or the risk considered, so the medical decision making that justified the level is invisible to a reviewer reading only the record.
The appeal succeeds only if the note already contains what is needed. Where it does, attaching it with a short explanation of how the elements map to the level billed is usually enough. Where it does not, the appeal is asking the payer to accept a level the record cannot support, and it should not be filed.
What sits behind it
CO-150 is a documentation denial that practices persistently treat as a coding denial. The coder chose the level from the note; the note is what failed the review. Responding by changing coding policy addresses the wrong end of the problem and typically pushes the practice toward undercoding, which costs more over a year than the denials did.
Since the 2021 revision of office and outpatient evaluation and management, level is determined by medical decision making or by total time, and the two are alternative routes rather than a combination. Notes that record neither cleanly — no explicit time statement, and decision making described only as a plan — support whatever a reviewer decides they support.
The durable fix is in the template rather than the coder. If the note prompts for data reviewed, risk considered, and total time when time is the basis, the elements are captured while the clinician still remembers the encounter. Reconstructing them at appeal, months later, is both weaker evidence and a compliance risk.
Related codes
Terms used here — E/M Coding · Undercoding · Medical Necessity
How we handle it — Medical Coding · Denial Management · Practice Analytics
Primary sources
The rules behind CO-150, at the bodies that publish them.
- Evaluation and Management services guide (opens in a new tab)
Centers for Medicare & Medicaid Services — How E/M level is determined under the current medical decision making and time rules. The reference for any dispute about whether documentation supports a level.
- OIG Work Plan (opens in a new tab)
HHS Office of Inspector General — What the OIG has said it will audit and when. The clearest available signal of which coding patterns are about to receive attention.
- Medicare claims appeals process (opens in a new tab)
Centers for Medicare & Medicaid Services — The five levels of appeal, what each requires and the deadline for each. Missing a level's deadline ends the appeal regardless of the claim's merits.
Every denial code with a guide
Authorization
Bundling
Contractual
Coverage
Data quality
Documentation
- CO-150Level of Service Not Supported
- CO-17Requested Records Not Received
- CO-252Attachment Required
Eligibility
Liability and workers comp
Patient responsibility
Provider eligibility
Timely filing
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-150
Usually not. The coder generally selected the level the note appeared to support; the note itself failed review. Treating it as a coding problem tends to push a practice toward undercoding, which costs more over a year than the denials did.
Only where the existing documentation genuinely supports the level billed. Then attach the note with a short explanation mapping its elements to the level. Where the record does not support it, the appeal asks the payer to accept something the note cannot evidence.
For office and outpatient visits since 2021, either medical decision making or total time on the date of the encounter — alternative routes, not a combination. Notes that document neither cleanly are the ones that generate this denial.
Fix the note template rather than the coding policy. Prompt for the data reviewed, the risk considered, and total time where time is the basis, so the elements are captured during the encounter rather than reconstructed at appeal.
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