CO-24 Denial Code: Charges Covered Under a Capitation Agreement or Managed Care Plan
CO-24 is a claim adjustment reason code meaning charges are covered under a capitation agreement or managed care plan. The most common trigger: billing traditional Medicare for a patient actually enrolled in a Medicare Advantage plan, or billing fee-for-service for a service already paid inside your capitation rate. Redirect the claim to the correct plan.
- Group
- CO (Contractual Obligation)
- Category
- Wrong payer / capitation
- Appealable?
- No; rebill the correct plan (MA plan or cap arrangement)
- Typical fix
- Verify enrollment, redirect claim to the Medicare Advantage or capitated plan
What does denial code CO-24 mean?
CO-24 means "charges are covered under a capitation agreement/managed care plan." Translation: the entity you billed says someone else already holds the financial responsibility, either a Medicare Advantage (MA) plan the patient is enrolled in, or a capitation contract that pays you a fixed per-member rate for this service instead of fee-for-service.
Classic example: a 72-year-old presents her Medicare card at check-in. You bill original Medicare for a level 3 visit, 99213, at $135.00. The remittance shows: billed $135.00, allowed $0.00, CO-24 $135.00, paid $0.00. Eligibility reveals she enrolled in a Humana MA-PD plan in January. The claim belongs to Humana, not the MAC.
Why did the claim get a CO-24?
- Medicare Advantage enrollment missed at check-in. The patient presented the traditional Medicare card, nobody ran eligibility, and the claim went to the MAC. This is by far the most common scenario.
- Service already inside your cap rate. Your IPA or HMO contract pays you monthly capitation for primary care, and you billed one of the capped CPT codes fee-for-service anyway.
- Carve-out confusion. Some services under a capitated contract are carved out and payable fee-for-service (immunizations are a frequent carve-out); billing the wrong bucket gets a CO-24 either direction.
- Mid-year plan switches during Medicare open enrollment (October to December) and the MA open enrollment period (January to March), when enrollment data goes stale fastest.
How do you fix and resubmit a CO-24 denial?
- Run eligibility for the date of service and identify the actual plan. For Medicare patients, the 271 response or the MAC portal will show the MA plan name and contract ID.
- Update the insurance on the account and rebill the correct payer, using that plan's payer ID and following its authorization and referral rules.
- If the denial came from a capitated contract, check your contract's covered-services matrix. If the code is capped, adjust it off; you were already paid via the monthly cap. If it is carved out, resubmit citing the carve-out language.
- Move fast: the correct plan's timely filing limit has been running since the date of service.
How do you prevent CO-24 denials?
Verify eligibility electronically at every visit and train the front desk that a Medicare card alone proves nothing about who pays; the 271 tells you whether an MA plan owns the patient. Keep a one-page matrix of your capitated contracts listing which CPT ranges are capped and which are carved out, and load those rules into your billing system so capped codes never release fee-for-service. Reconcile your monthly capitation rosters against your schedule; patients on the roster you billed FFS, and patients you saw who fell off the roster, are both revenue leaks.
Can you appeal a CO-24 denial?
There is rarely anything to appeal because the denying payer genuinely does not owe the claim; the fix is redirection, not argument. The exception is a capitation dispute: if the plan denies a carved-out service as capped, file a contract dispute with the plan or your IPA, attaching the contract's carve-out exhibit. Use the denial code lookup to confirm the remark codes, and the appeal deadline calculator to protect your window at the correct payer while the dispute runs.
Frequently asked questions
The payer is saying this service is already covered under a capitation agreement or a managed care plan, so it will not pay fee-for-service. In practice it most often means you billed original Medicare while the patient is enrolled in a Medicare Advantage plan, which is where the claim belongs.
Patients enrolled in Medicare Advantage keep their red-white-and-blue Medicare card and frequently present it instead of the MA plan card. Original Medicare sees the MA enrollment on file and denies CO-24. Check eligibility, identify the MA plan, and bill that plan directly.
No. The Medicare Advantage or capitated plan's own filing limit applies from the date of service. Many MA plans allow 90 days to one year. If the CO-24 denial ate most of that window, submit immediately and include the original Medicare denial as proof of your good-faith filing.
Sources & further reading
Reviewed by the ImmediCare Solutions RCM team
Certified billers and coders handling claims across 50+ specialties nationwide. This entry is reviewed against current payer policy and CMS rules. Last review: Jul 5, 2026.
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