CO-256 Denial Code: Service Not Payable Per Managed Care Contract

What Does CO-256 Mean?

CO-256 means your managed care contract itself is the reason for non-payment — the payer is pointing at terms you agreed to: services outside your contracted scope, sites not covered by your agreement, rates bundled into other payments, or provisions that make this claim non-payable as billed.

Code group: CO (Contractual Obligation) · Appealable: Very — when the contract is misapplied, the document itself wins the dispute. True scope exclusions are business decisions, not appeals.

Why CO-256 Happens

The service isn't in your contracted scope — your agreement covers certain service categories, and this claim falls outside them.
Site-of-service restrictions: the contract pays this service in office but not facility (or vice versa), or your agreement covers specific locations only.
The contract bundles this service into another payment — a global rate, case rate, or per-diem that already includes it.
Referral or network-tier rules in the contract weren't met — the plan design routes this service to designated providers.
The payer is misapplying the contract — reading a provision wrong, using a stale version, or applying another group's terms to your claims.

How to Fix a CO-256 Denial — Step by Step

Get the denial's specifics: which contract provision? Payers citing CO-256 should be able to name the term — make them.

Pull your actual executed contract and read the cited section. A meaningful share of CO-256 denials misapply the contract, and the document settles it.

If the payer is wrong, dispute with the contract language attached — these overturn cleanly because the evidence is black and white.

If the contract genuinely excludes the service, decide the business question: stop providing it under that plan, renegotiate scope at renewal, or (where the contract and law allow) establish patient-pay arrangements with advance notice.

Track CO-256 by payer and provision — patterns here are contract-negotiation ammunition, not just denial noise.

CO-256 Appeal Letter Template

Adapt this wording to your claim — replace the bracketed fields and attach the documentation it references:

'Claim [number] was denied CO-256 citing [provision]. Our executed agreement effective [date], section [ref] (attached), provides for payment of [service/CPT] at [rate/terms]. The denial misapplies the contract, and we request reprocessing per the agreement.' When the payer can't name a provision, demand one — unspecified contract denials rarely survive a documented challenge.

How to Prevent CO-256

Keep executed contracts, amendments, and fee exhibits organized and accessible to billing — you can't fight contract denials without the contract.
Map your service lines against each contract's scope before adding new services or sites.
Raise recurring CO-256 categories at every contract renewal; exclusions you keep eating are negotiating points you keep missing.

Related Denial Codes

CO-24 — Capitation / managed care CO-45 — Exceeds fee schedule CO-96 — Non-covered charges

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Reviewed by the LegitMedBilling denial management team. This guide is general billing information, not legal or payer-specific advice — always verify against your payer contract and current policy.

Frequently Asked Questions

The payer won't tell us which contract provision applies. What now?

Put the question in writing and escalate through provider relations — a payer denying on contract grounds owes you the provision. Meanwhile, review your own copy for anything plausibly relevant. Unspecified CO-256 denials have poor survival rates against a provider who shows up with the executed agreement.

Can we bill the patient for a CO-256 denial?

Generally no — the CO prefix makes it a contractual write-off, and managed care agreements usually prohibit balance billing for services denied under contract terms. Exceptions exist where the contract explicitly permits patient-pay arrangements with advance notice; check yours before any patient billing.

How is CO-256 different from CO-24?

CO-24 says the care is covered under a capitation or managed-care arrangement (payment routes elsewhere or already happened via cap). CO-256 says your contract's terms make this specific claim non-payable. CO-24 is about who pays; CO-256 is about what your agreement covers — and it's the one you fight with the contract document itself.