CO-26 — Expenses incurred before coverage began
Claim-adjustment reason code 26 · typically reported as CO-26 or PR-26
What it means
The date of service is earlier than the patient’s effective date with this payer.
Why DME claims hit it
- Delivery before a plan’s effective date during open-enrollment switches
- Rental span straddling an enrollment change
How to fix it
- Confirm the effective date via eligibility; bill the payer that was active on the DOS
- For rentals, split the billing at the coverage transition
Appeal posture
Only with proof the eligibility record is wrong.
Related denial codes
CO-27 — Expenses incurred after coverage endedPR-31 — Patient cannot be identified as insuredCO-177 — Patient hasn’t met eligibility requirements
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