Denial Code 26 (CO-26, PR-26) — Meaning & What to Do

Claim Adjustment Reason Code (CARC)

What denial code 26 means: Expenses were incurred before your coverage started.
What to do about denial code 26: If your coverage was active, ask the insurer to correct the dates.

CO-26 vs PR-26 vs OA-26: what the prefix means

Code on your EOBWhat the prefix meansWho typically pays
CO-26Contractual obligation — the provider writes the amount offUsually not the patient
PR-26Patient responsibilityThe patient
OA-26Other adjustmentOften another payer or plan

The prefix tells you who is expected to absorb the amount; the number (26) tells you why.

Related codes

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Frequently asked questions about Denial code 26

What does denial code 26 mean on my EOB?

Expenses were incurred before your coverage started.

What should I do about denial code 26?

If your coverage was active, ask the insurer to correct the dates.

Found this code on your bill or EOB?
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Last reviewed 2026-07-07 · MDBillCheck Editorial Team. Plain-English explanations are original wording; always verify the specific reason with your insurer.