Healthcare Error Code
Healthcare Insurance / Medical Billing
Claim Adjustment Reason Codes (CARC)
CO-33 | Insufficient documentation
Industry
Healthcare
Canonical
/healthcare/error-codes/co-33/
Last Updated
Feb 25, 2026
Summary
This code indicates that documentation provided was not sufficient to support the claim.
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What This Code Means
CO-33 is used when the payer determines that documentation does not adequately support payment. This relates to documentation completeness or relevance. It is not a coverage exclusion by itself. The service may still qualify for payment if adequate documentation is provided. The code reflects administrative review standards.
Where Users Usually See This Code
- Remittance advice
- Documentation review notices
- EOB remarks
Why This Code Appears
- Required documentation not submitted
- Documentation did not meet payer standards
- Insufficient clinical or administrative detail
What Typically Happens Next
- Payment is denied or delayed
- Additional review may be required
- Claim may be finalized pending action
What This Code Is Not
- It is not a billing format error
- It is not a duplicate claim
- It is not a contractual adjustment
Troubleshooting Checklist
- □ Review documentation requirements
- □ Confirm completeness of records
- □ Monitor review timelines
Notes And Edge Cases
Documentation standards vary by payer. Requests may arise during audits or prepayment review.
Related Codes
8 links
- CO-178 CodeClaim did not contain sufficient information
- N286 CodeMissing/incomplete documentation
- CO-27 CodeCoverage terminated
- CO-197 CodePrecertification required
- CO-26 CodeExpenses incurred before coverage
- CO-133 CodeIncorrect provider type
- CO-11 CodeDiagnosis inconsistent with procedure
- CO-21 CodeMissing/invalid place of service
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