Healthcare Error Code
Healthcare Insurance / Medical Billing
Authorization / Medical Necessity
CO-26 | Expenses incurred before coverage
Industry
Healthcare
Canonical
/healthcare/error-codes/co-26/
Last Updated
Feb 25, 2026
Summary
This code indicates that the service was provided before insurance coverage became effective.
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What This Code Means
CO-26 is used when a payer determines that expenses were incurred outside the active coverage period. Coverage effective dates define when benefits apply. Services provided before coverage begins are typically not reimbursable. This is a coverage timing issue rather than a billing or documentation error. It does not reflect on service quality.
Where Users Usually See This Code
- EOB statements
- Remittance advice
- Coverage eligibility summaries
Why This Code Appears
- Service date precedes coverage effective date
- Enrollment start date was after service
- Coverage activation delays occurred
What Typically Happens Next
- Payment is denied
- Responsibility may shift to the patient
- The claim is finalized
What This Code Is Not
- It is not a coding error
- It is not a contractual adjustment
- It is not a temporary hold
Troubleshooting Checklist
- □ Verify coverage effective dates
- □ Review enrollment records
- □ Confirm eligibility timelines
Notes And Edge Cases
Retroactive coverage changes may affect how this code appears. Some plans allow limited retroactive eligibility.
Related Codes
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