CO-9 — Diagnosis inconsistent with patient age
Claim-adjustment reason code 9 · typically reported as CO-9
What it means
The diagnosis code on the claim doesn’t line up with the patient’s age (e.g., a pediatric-only diagnosis on an adult claim).
Why DME claims hit it
- Pediatric equipment dx codes carried over to adult re-orders
- Typo in date of birth at intake
How to fix it
- Verify DOB against the insurance card/270 response
- Correct the dx or the DOB and resubmit
Appeal posture
Resubmit corrected; appeal only if the payer’s age edit is wrong.
Related denial codes
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