CO-204: Service not covered under the current benefit plan
UPDATED JULY 2026 · U.S. PLANS · NOT LEGAL OR MEDICAL ADVICE
The payer says this service, drug, or supply simply isn't a benefit of your plan. For medications this often means a formulary exclusion — which has its own exception process.
CO-204 at a glance
- Code group: CO — Contractual Obligation — in-network providers generally cannot bill you for CO adjustments.
- Who usually fixes it: You (the member).
- Worth appealing? Yes — commonly appealed.
What to do about a CO-204 denial
- For drugs: file a formulary exception with your prescriber's support.
- For services: ask the insurer to cite the exclusion, then compare against your Evidence of Coverage.
- Appeal when the plan language covers your situation or an exception pathway applies.
Best next read: Formulary / drug-not-covered denials — the full guide (with a free letter template) for this denial type.
Denied? Don’t drop it
Upload your denial letter. Get the whole appeal packet.
GetMyYes reads the actual letter — codes, fine print, deadlines — and drafts your appeal letter, evidence checklist, doctor letter request, and call script. Free preview first.
Start my appeal — free previewFREE PREVIEW · $39 FULL PACKET · NO SUBSCRIPTION. EVER.