EOB denial code · CO group
CO-204: Incorrect Provider Requested — Meaning & Fix
CO-204 means the claim was submitted under a provider the plan says is incorrect — a wrong NPI, a terminated provider number, the wrong group, or a service rendered by an assistant/tech under the wrong rendering provider. It's a billing-key error: the claim must be corrected to the provider who actually rendered the service, then resubmitted.
What “CO-204” means on your EOB
The claim/service was submitted with the incorrect provider requested or the provider requested is not eligible for payment.
Who pays? CO — Contractual Obligation
CO (contractual) — the denial is a provider-record error; you aren't the payer of last resort while it's unfixed.
What to do next: Ask the billing office to verify: the rendering provider's NPI, the billing provider's NPI, group/subsidiary TIN, and whether a locum tenens or employed-provider arrangement needs special coding. Once the correct provider is attached, payers reprocess quickly.
Why this denial happens
- Wrong rendering NPI (e.g., the physician vs the midlevel who actually saw you).
- The billing group's TIN/NPI doesn't match the plan's contract.
- A service was performed at a facility but billed under the wrong location provider.
- The provider's enrollment with the payer lapsed or the ID was terminated.
What to do now
- Confirm who actually rendered the service (notes or the visit summary).
- Ask billing to verify the rendering and billing NPIs against the payer's records.
- Request a corrected claim with the correct provider identifiers.
- If the provider's enrollment lapsed, ask them to re-enroll and reprocess — most payers back-date payment once enrollment is restored.
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Generate an appeal letter →What is an NPI?
The National Provider Identifier — a 10-digit number every provider and group uses to bill. CO-204 often means the wrong number was attached to the claim.
Do I owe anything for CO-204?
Not while the claim carries the wrong provider — it couldn't be adjudicated correctly. Get it corrected and reprocessed first.
Why does it matter which provider is on the claim?
Insurance contracts, network status, and coverage rates attach to specific providers and groups. The wrong NPI can turn an in-network service into a 'wrong provider' denial.