Key Takeaways:

• The CO-24 denial code means “Charges are covered under a capitation agreement/managed care plan.” The provider has already received a fixed payment for the patient’s care.
• “CO” stands for Contractual Obligation. The provider absorbs the denied amount and can’t bill the patient.
• Most common trigger: billing Original Medicare when the patient is enrolled in a Medicare Advantage (Part C) plan.
• Over 35 million Americans are in Medicare Advantage as of 2026. CO-24 denials are rising across all practice types.
• Correct appeal timelines: 120 days for Original Medicare, 60 days for MA plan payment disputes.
• Most CO-24 denials are preventable with proper eligibility verification and capitation contract awareness.

41% of healthcare providers now see more than one in ten claims denied, according to Experian Health’s 2025 State of Claims report. Three years earlier, that number was 30%.

KFF and CMS report over 35 million Americans enrolled in Medicare Advantage as of February 2026. With that many patients in managed care, capitation-related denials like CO-24 keep climbing across every practice type.

Denial codes are the payer’s explanation for why a claim wasn’t paid. Each one points to a specific problem. Get the code right, and you know where to focus. Skip that step, and revenue disappears. That’s where effective denial management starts.

The CO-24 denial code shows up frequently in practices treating Medicare Advantage, Medicaid managed care, and HMO patients. Billing teams misinterpret it, confuse it with other contractual codes, or write it off without checking if the denial was even correct.

Here’s the thing: not every CO-24 denial is legitimate. The ones that aren’t represent recoverable revenue sitting untouched on your aging report.

This guide breaks down what CO-24 means, why it happens, and how to resolve it step by step. You’ll also find the real financial impact on your practice and how to prevent these denials from recurring. All content reflects 2026 data and current CMS guidance.

What Is the CO-24 Denial Code?

Understanding this code comes down to three things: what it means, what the “CO” group code tells you, and who’s responsible for the denied amount.

CO-24 Denial Code Definition

The CO-24 denial code is a Claim Adjustment Reason Code (CARC). It indicates a claim was denied because the billed service is covered under a capitation agreement or managed care plan.

What’s happening is straightforward. The payer already compensated you through a fixed, pre-negotiated payment, typically calculated on a per member per month (PMPM) basis. You can’t bill that service separately because the payer considers it already paid for.

Here’s what CO-24 is not: a medical necessity denial, a timely filing rejection, or a fee schedule overcharge. This code is exclusively about capitation and managed care coverage.

A few guides online incorrectly define CO-24 as a “denied miscellaneous payment” or connect it to medical necessity. That’s factually wrong, and basing your appeal strategy on a bad definition means chasing the wrong fix.

Official CARC Description for Code 24:
“Charges are covered under a capitation agreement/managed care plan.”
Source: Washington Publishing Company (WPC) / ASC X12| Last Reviewed: March 1, 2026

What Does “CO” (Contractual Obligation) Mean?

The “CO” in CO-24 stands for Contractual Obligation. It controls what you can do with the denied amount.

When a denial carries the CO group code, you’re contractually responsible for the adjustment. You can’t bill the patient or send it to collections. It’s a write-off under your payer contract.

CMS’s Medicare remittance guidance states that CO adjustments are “generally write-offs and are not billed to the patient.” Noridian, a Medicare Administrative Contractor, clarifies: “The beneficiary may not be billed for these amounts.”

Compare with two other group codes:

• PR (Patient Responsibility): Patient owes the denied amount.
• OA (Other Adjustment): Payer-initiated adjustment; neither you nor the patient is responsible.

CO-24 vs. PR-24: Who Is Responsible for Payment?

This distinction trips up billing staff more than you’d expect. Getting it wrong creates real compliance exposure.

Billing a patient for a CO-24 amount isn’t just a billing error. It’s a compliance violation under most payer contracts and may violate state balance-billing laws.

When CO shows up on the remit, the patient conversation stops before it starts. That amount sits between you and the contract terms. The patient doesn’t owe a thing.

Treat every denial the same and you’ll miss this distinction. PR-24 amounts go uncollected while CO-24 amounts get billed to patients incorrectly. Both cost money. One also creates legal exposure.

CO-24 Denial Code Description: What It Means in Plain Language

The CO-24 denial code description, per the official CARC code set maintained by X12 and last reviewed on March 1, 2026, states: “Charges are covered under a capitation agreement/managed care plan.”

In plain language, the payer already paid you a fixed monthly amount to cover that service. No additional payment is coming.

A capitation agreement is a contract between a provider and a managed care organization (MCO). The MCO pays you a fixed fee, typically per member per month (PMPM), regardless of how many services that patient receives during the coverage period.

CMS’s Medicare Managed Care Manual defines capitation as “a set dollar payment per patient per unit of time, usually per month, paid to cover a specified set of services without regard to the actual number of services provided.”

Since you’ve already been compensated through that fixed payment, submitting a separate fee-for-service claim triggers the denial. The payer’s system checks enrollment, confirms the capitation contract covers the service, and rejects the charge.

This applies across outpatient visits, lab tests, diagnostic imaging, inpatient stays, and specialist consults. If the service falls within the scope of the capitation contract, you can’t bill it separately.

Several guides online define CO-24 as a “denied miscellaneous payment” or a “medical necessity” denial. That’s factually wrong. CO-24 has nothing to do with medical necessity or fee schedules. It’s exclusively about the capitation payment model.

Service Covered Under a Capitation Agreement

Simplest trigger on the list. The patient is in a capitated plan, and your practice receives a fixed monthly payment. When billing staff submit a separate claim for a service that payment already covers, the payer denies it. They’ve already paid. Your claim asks them to pay twice.

Claim Submitted to the Wrong Payer

This comes up constantly with Medicare patients. A patient has Medicare Advantage (Part C), but the claim goes to Original Medicare (Parts A/B). Original Medicare sees the managed care enrollment and kicks it back with CO-24.

Routing it to the correct MCO fixes the problem. But the rework time is already gone, usually 14 to 30 days of delayed resolution.

Missing Prior Authorization or Referral

Some managed care plans require prior authorization before certain services. Skip that step and the claim gets denied. Not because the service lacked medical necessity, but because the plan’s administrative process wasn’t followed. Procedural denial, not clinical.

Out-of-Network Provider

If your practice isn’t contracted with the patient’s managed care plan, the MCO may deny under CO-24. A lot of managed care plans restrict coverage strictly to in-network providers.

Provider enrollment and credentialing matters on the front end. If you aren’t credentialed before delivering care, you’re setting up denials that are nearly impossible to overturn.

Outdated Coordination of Benefits (COB) Information

Patients with multiple insurance plans create routing problems. Someone has Medicare plus a supplemental plan or Medicaid plus a managed care plan, and the COB hasn’t been updated. Claims end up at the wrong payer. That wrong payer sends back CO-24.

Usually it’s a registration issue. COB wasn’t collected at check-in or wasn’t verified since the patient’s last visit.

Expired Capitation Agreement

Nearly every billing guide out there misses this one. A CO-24 denial can happen when the capitation agreement between your practice and the MCO has expired, but claims are still going out under the old terms.

When a contract hasn’t been renewed or renegotiated, the payer may deny claims because the capitation terms aren’t active anymore. Build contract renewal dates into your billing calendar.

AI-Driven Automated Denials (Emerging Trend)

Payers are increasingly deploying artificial intelligence to adjudicate claims automatically. These AI systems scan for capitation-related billing patterns and deny claims in bulk.

The issue is these systems aren’t always accurate. They flag services that might be carved out of the capitation agreement. Claims get denied based on enrollment data that’s outdated on the payer’s end. And it happens at scale, so a single system error can generate a wave of CO-24 denials that aren’t all legitimate.

Proactive denial management and human review of denied claims aren’t optional anymore when payers are automating at this pace.

Managing CO-24 denials takes time your billing team may not have. One O Seven RCM’s denial management services identify root causes, handle appeals, and implement prevention protocols, so you can focus on patient care.

Why CO-24 Denials Are Rising: The 2026 Medicare Advantage Reality

CO-24 isn’t showing up on your remits more often by coincidence. Two forces are driving it: Medicare Advantage enrollment keeps growing, and denial rates across the board are sitting at historic highs. If your team has noticed a jump in capitation-related denials over the past year, the numbers below explain why.

Medicare Advantage Enrollment Has Passed the Tipping Point

According to KFF and CMS data from February 2026, just over 35 million people are now enrolled in Medicare Advantage. That’s an increase of 1.1 million from February 2025, representing 3% year-over-year growth.

Some perspective helps here. Back in 2007, only 8 million Medicare beneficiaries were in MA plans. That was 19% of the eligible population. Now it’s past 54%. More than half of all Medicare patients are in managed care.

Access isn’t the issue either. Over 99% of beneficiaries can choose from at least one MA plan, with an average of 32 options per person.

Here’s what that means at the front desk: the chances of accidentally billing Original Medicare for a patient who’s actually in a managed care plan have never been higher. MA verification needs to be part of every intake workflow.

The Denial Crisis Is Accelerating

Experian Health’s 2025 State of Claims report found that 41% of providers now report more than 10% of their claims are denied. In 2022, that number was 30%. By 2024, it hit 38%.

Medicare Advantage makes it worse. A Health Affairs study published in June 2025 found MA plans deny 17% of initial claim submissions. Of those, 57% were ultimately overturned on appeal. But the net impact was still a 7% reduction in provider MA revenue.

Overall initial denial rates reached 11.8% in 2024, up from 10.2% just a few years prior.

Capitation-related denials like the CO-24 denial code are especially damaging within this trend. They don’t usually stem from one-off coding mistakes. Most point to systematic workflow issues, which means they keep recurring until someone fixes the root cause.

Common Causes of the CO-24 Denial Code

The CO-24 denial code can trace back to billing errors, eligibility gaps, contractual misunderstandings, and increasingly, automated payer systems. Understanding the root cause behind each denial is how you stop the same ones from landing on your aging report month after month. Here are the seven triggers that come up most often.

Service Covered Under a Capitation Agreement

Most straightforward trigger on the list. Your patient is enrolled in a capitated plan, and the practice receives a fixed monthly payment for their care. When billing staff submit a separate claim for a service that payment already covers, the payer denies it.

They’ve already paid. The claim asks them to pay a second time.

Claim Submitted to the Wrong Payer

This one shows up constantly with Medicare patients. Someone has Medicare Advantage (Part C), but the claim gets submitted to Original Medicare (Parts A/B). Original Medicare checks enrollment, sees the MA plan, and sends the claim back with CO-24.

Routing it to the correct MCO solves the problem in theory. In practice, the rework has already cost you 14 to 30 days of delayed resolution.

Missing Prior Authorization or Referral

Certain managed care plans won’t pay without prior authorization before the service. Miss that step and the claim comes back denied. Not because the care was medically unnecessary, but because the plan’s administrative requirements weren’t met.

That’s a procedural denial, not a clinical one. Providers find these especially frustrating because the care was appropriate. The paperwork just wasn’t in place.

Out-of-Network Provider

When your practice isn’t contracted with the patient’s managed care plan, the MCO can deny the claim under CO-24. A lot of plans restrict coverage strictly to in-network providers, and there’s usually no negotiating after the fact.

This is why provider enrollment and credentialing matters on the front end. Deliver care before you’re credentialed with that MCO, and you’re creating denials that are nearly impossible to overturn.

Outdated Coordination of Benefits (COB) Information

Patients carrying multiple insurance plans create routing headaches. Someone has Medicare plus a supplemental plan, or Medicaid plus a managed care plan, and the COB hasn’t been updated. Claims go to the wrong payer. That payer sends back CO-24.

Root cause is almost always at registration. COB wasn’t collected at check-in or wasn’t reverified since the patient’s last visit.

Expired Capitation Agreement

Nearly every billing guide online overlooks this one. A CO-24 denial can show up when the capitation agreement between your practice and the MCO has expired, but claims keep going out under old contract terms.

If the contract hasn’t been renewed or renegotiated, the payer may deny because the capitation arrangement is no longer active. Build contract renewal dates into your billing calendar so this doesn’t catch you by surprise.

AI-Driven Automated Denials (Emerging Trend)

Payers are deploying artificial intelligence to adjudicate claims automatically. These AI systems scan for capitation-related billing patterns and deny claims in bulk.

Automated systems aren’t always accurate. They flag services that might actually be carved out of the capitation agreement. They reject claims using enrollment data that’s stale on the payer’s end. One system error can trigger a sudden spike in CO-24 denials, and not all of them are legitimate.

Proactive denial management and human review of denied claims aren’t optional when payers are automating at this pace.

Managing CO-24 denials takes time your billing team may not have. One O Seven RCM’s denial management services identify root causes, handle appeals, and implement prevention protocols, so you can focus on patient care.

CO-24 Denial Code in Medicare vs. Medicaid

CO-24 denials play out differently depending on the payer. Medicare and Medicaid each run their own managed care structures, and the billing mistakes that trigger this code vary between them. Knowing the payer-specific nuances helps your team route claims correctly the first time.

CO-24 Medicare Denial: Medicare Advantage Billing Errors

The most common CO-24 Medicare denial happens when a provider bills Original Medicare (Parts A/B) for a patient enrolled in a Medicare Advantage plan (Part C).

Medicare Advantage plans are run by private insurers like UnitedHealthcare, Humana, and Aetna. Once a patient enrolls, that plan replaces Original Medicare for most services. Claims go to the MCO, not to CMS.

Noridian, a Medicare Administrative Contractor, states: “If a patient has a Medicare Advantage/HMO plan, CO-24 will display on the remit.” Their recommended workflow: verify eligibility in the Medicare portal, and if an MA plan is active, bill the appropriate insurer.

Check enrollment through CMS’s provider enrollment tools or the patient’s insurance card. Then submit the claim to the correct Medicare Advantage plan. Never assume every Medicare patient is on Original Medicare.

CO-24 Medicaid Denial: State-Specific Managed Care Considerations

Most states have moved Medicaid beneficiaries into managed care plans administered by Medicaid MCOs. When a provider bills the state’s fee-for-service Medicaid program for a patient enrolled in a Medicaid MCO, the claim comes back as CO-24.

Here’s where it gets complicated. Some states carve specific services out of managed care. Behavioral health is a common one. Dental is another. Carved-out services should be billed to the state Medicaid program, not the MCO. What’s capitated in Texas might be carved out in New York.

Always verify the patient’s Medicaid managed care enrollment through your state’s Medicaid portal or eligibility verification system before submitting claims. Your state’s Medicaid managed care page lists active MCOs and covered services by plan.

Key Exceptions: Hospice Care and Clinical Trials

Even when a patient has a Medicare Advantage plan, Original Medicare still covers hospice services. This is the one major exception to the “bill the MA plan” rule.

When you’re providing hospice-related care to an MA patient, bill Original Medicare with the correct modifiers:

• GV modifier: Attending physician not employed or paid by the patient’s hospice provider
• GW modifier: Service not related to the hospice patient’s terminal condition

Original Medicare also covers routine costs of qualifying clinical trials for MA patients. Use modifier Q0 for investigational clinical services or Q1 for routine clinical services.

Without these modifiers, claims for hospice or clinical trial services trigger CO-24 even when Original Medicare should be paying. Miss the modifier, and you’ve created a denial that didn’t need to exist.

Navigating payer-specific denial rules across Medicare, Medicaid, and commercial plans is complex. One O Seven RCM’s denial management specialists resolve capitation-related denials daily, and provider credentialing at $99 per insurance ensures your practice is enrolled with the right MCOs from the start.

How to Resolve the CO-24 Denial Code: Step-by-Step

When a CO-24 denial lands on your desk, a systematic approach keeps you from chasing the wrong fix. Not every CO-24 requires an appeal. Some need a corrected claim. Others call for a clean write-off. These six steps tell you which path to take.

Step 1: Review the ERA/EOB and Identify the CARC/RARC

Start with the Electronic Remittance Advice (ERA) or Explanation of Benefits (EOB). Find the CARC code (CO-24) and check for any accompanying Remittance Advice Remark Codes (RARCs).

The RARC often tells you more than the CARC alone. It may clarify whether the denial stems from capitation, incorrect payer routing, or a COB issue. That distinction changes your next move entirely.

Don’t skip this. Two minutes of review saves hours of guessing.

Step 2: Verify Patient Eligibility and Capitation Status

Confirm the patient’s insurance enrollment as of the date of service. Was the patient actually in a capitated plan when you provided care? Check through the payer’s eligibility portal, call the MCO, or look it up in your practice management system.

Noridian’s guidance for Medicare claims is direct: “Verify the patient’s eligibility information on the Medicare portal and submit the claim to the listed HMO or MA plan.”

Patients switch plans mid-month. Retroactive enrollment changes happen. Someone who looked like a valid fee-for-service patient at check-in may have already been capitated by the date of service. That’s where comprehensive medical billing services catch issues your front desk might miss.

Step 3: Check Capitation Contract Terms (Carved-Out vs. Bundled)

Pull your capitation contract with the relevant MCO. Figure out whether the denied service is bundled into the capitation payment or carved out for separate billing.

A lot of contracts carve out specific services: lab work, specialty referrals, durable medical equipment, certain procedures. If the denied service sits on the carved-out list, the CO-24 denial may be wrong.

Keep a reference sheet for each payer listing what’s capitated and what isn’t. When your team can look this up in 30 seconds instead of digging through a 40-page contract, resolution speeds up considerably.

Step 4: Redirect the Claim or Write Off the Amount

Two possible outcomes here, and they require opposite actions.

Wrong payer? If the claim went to Original Medicare instead of the MA plan, or to state Medicaid FFS instead of a Medicaid MCO, contact the correct insurer. Verify your participation status, obtain any needed authorization, and resubmit. That’s a routing correction, not a formal appeal.

Legitimate capitation? Write off the denied amount as a contractual adjustment. Don’t bill the patient. CO-24 carries the CO group code, which means the patient isn’t responsible.

Step 5: Check for Modifier Exceptions (Hospice and Clinical Trials)

Before accepting a CO-24 denial on a Medicare claim, check whether the service qualifies for a billing exception.

Hospice care for MA patients should go to Original Medicare with the right modifier:

• GV: Attending physician not employed by the patient’s hospice provider
• GW: Service unrelated to the terminal condition

Clinical trial services for MA patients also go to Original Medicare:

• Q0: Investigational clinical service
• Q1: Routine clinical service

Without these modifiers, legitimate claims trigger CO-24 even when Original Medicare should be paying. Miss the modifier, and you’ve turned a payable claim into a denial.

Step 6: File an Appeal if the Denial Is Incorrect

When you’ve confirmed the service is carved out, the patient wasn’t in managed care at the time of service, or the denial was a payer system error, file a formal appeal.

Missing the appeal deadline converts a potentially recoverable denial into a permanent write-off.

Include with your appeal the capitation contract section showing the service is carved out, patient eligibility records from the date of service, prior authorization documentation if applicable, and a cover letter explaining specifically why the denial is incorrect.

Generic appeal letters get generic results. Payer appeals teams process thousands of these. The ones with clear documentation and a specific argument get resolved. The vague ones sit in a pile.

If your practice struggles to keep up with appeal deadlines and payer follow-up, tightening your AR follow-up and appeals process is where the money comes back.

How to Prevent CO-24 Denials: 5 Proactive Steps

Prevention costs almost nothing. Resolution costs staff hours, delayed revenue, and administrative headaches. These five front-end controls, built into your daily workflow, can cut CO-24 denial rates significantly, often within the first billing cycle.

Step 1: Verify Eligibility and Capitation Status Before Every Visit

Before any patient encounter, check whether their coverage falls under a capitation agreement or managed care plan. Real-time eligibility verification tools make this a 30-second task. Query the payer’s portal directly or look at the patient’s insurance card for MCO information.

Flag capitated patients in your practice management system. When billing staff see that flag before submitting a claim, they know not to send a separate fee-for-service charge for bundled services. That one flag prevents the most common CO-24 trigger.

Step 2: Know Your Capitation Contracts Inside and Out

Keep copies of every capitation contract your practice has signed. Build an internal reference sheet for each payer listing which services are bundled and which are carved out for separate billing.

Contracts change. Payers renegotiate terms. A service that was carved out last year might be bundled this year. Review contracts at every renewal and update your reference sheets right away. Pay close attention to expiration dates so you don’t end up billing under an agreement that’s no longer active.

Step 3: Confirm the Payer Hierarchy (Coordination of Benefits)

Patients carrying multiple insurance plans create routing problems. Always check Coordination of Benefits to determine payer order: primary, secondary, tertiary.

Submitting to the wrong payer in the hierarchy is one of the top CO-24 triggers. Collect COB information at registration and verify it at every visit. Patients don’t always mention that they’ve picked up new coverage since their last appointment.

Step 4: Train Billing and Front-Desk Staff Regularly

Your team can’t prevent what they don’t understand. Make sure billing staff, front desk employees, and clinical team members all grasp the basics: what capitation means, how to spot capitated patients, which services can’t be billed separately, and how to verify payer information.

Quarterly refresher sessions work well. So does a quick training update whenever a new payer contract is signed. The investment in training pays for itself many times over in avoided rework.

Step 5: Use Technology to Flag Capitated Claims Before Submission

Modern billing and practice management software can catch CO-24 triggers before claims ever leave your office. Set up claim scrubbing rules that check for capitation status. Configure automated alerts for patients enrolled in managed care plans.

According to Experian Health’s 2025 data, 69% of providers who use AI-driven tools report fewer denials and more successful resubmissions. Yet only 14% of providers have adopted these tools. Early adopters are seeing measurable results while everyone else keeps reworking the same claims.

Integrating these prevention steps into your revenue cycle management workflow turns denial prevention from a reactive scramble into a built-in safeguard.

Can You Appeal a CO-24 Denial?

Yes, you can appeal a CO-24 denial. But not every CO-24 should be appealed.

When to appeal: Three scenarios make it worth the effort.

• The denied service is carved out of the capitation agreement
• The patient wasn’t enrolled in the managed care plan at the date of service
• A payer system error triggered an incorrect denial, which is increasingly common with AI-driven claims adjudication

When not to appeal: If the service is legitimately included in the capitation payment, the denial is valid. Write it off as a contractual adjustment. Filing an appeal you can’t win wastes your team’s time and clogs the payer’s review queue.

Watch the deadlines. Original Medicare gives you 120 days from the remittance advice date for a redetermination. CMS requires Medicare Advantage plans to process provider payment disputes within 60 days. Commercial payers typically allow 90 to 180 days for first-level appeals. Medicaid MCOs follow state-specific rules, and some states allow as few as 60 days.

Build a strong appeal package. Include the capitation contract section showing the service is carved out, eligibility records from the date of service, and any prior authorization documentation. Add a cover letter that explains specifically why the denial is incorrect.

Here’s the thing: payer appeals teams review thousands of these. A well-documented appeal with a clear, specific argument gets attention. A vague letter with no supporting records gets set aside. The difference between recovering that revenue and losing it permanently often comes down to how you package the appeal.

Financial Impact of CO-24 Denials on Your Practice

Unresolved CO-24 denials don’t just create paperwork. They drain revenue, tie up staff, and slow down your entire billing operation. Here’s what the numbers actually look like.

Put those numbers in context. A practice processing 500 claims per month with even a 5% CO-24 denial rate is looking at 25 denied claims. At $25 to $30 in rework costs per claim, that’s $625 to $750 in administrative costs alone, before counting the delayed or lost revenue from the denied services themselves.

Medicare Advantage makes this picture worse. A Health Affairs study published in June 2025 found that MA plans deny 17% of initial claim submissions. Of those, 57% were ultimately overturned on appeal. But the net result was still a 7% reduction in provider MA revenue.

For capitation-related denials like CO-24, where the issue is usually a routing error rather than a clinical question, the overturn rate can be higher when practices have solid appeal processes. That’s recoverable money sitting on your aging report.

Investing in proactive denial management and accurate billing processes delivers measurable ROI, often within the first billing cycle.

One O Seven RCM helps healthcare providers recover revenue lost to denials like CO-24, with full-service medical billing at just 2.99% of collections and provider credentialing at $99 per insurance. Our denial management specialists maintain one of the highest denial recovery rates in the industry. See how we can help →

CO-24 vs. Related Denial Codes: Key Differences

The CO-24 denial code gets mixed up with other contractual obligation codes more often than it should. Each code points to a different root cause and needs a different resolution approach. Treating them the same way guarantees you’ll fix the wrong thing.

Here’s why the distinction matters. Treating a CO-24 like a CO-45 means adjusting your fee schedule when the real issue is capitation enrollment. That doesn’t fix anything. The denial keeps recurring because you solved the wrong problem.

CO-22 is the one that trips people up most. Both CO-22 and CO-24 involve payer routing, but CO-22 says “try a different payer in the COB hierarchy,” while CO-24 says “this service is already paid for under capitation.” Different root cause, different fix.

If you’re seeing multiple denial codes across your claims, a systematic denial management review can uncover patterns and address root causes across all code categories.

Frequently Asked Questions About the CO-24 Denial Code

What does CO-24 denial code mean?

The CO-24 denial code means the billed service was denied because it’s covered under a capitation agreement or managed care plan. The provider already received a fixed payment for the patient’s care, so separate fee-for-service billing for included services isn’t allowed. The “CO” group code marks this as a contractual obligation, meaning the patient can’t be billed.

What does “charges are covered under a capitation agreement/managed care plan” mean?

This phrase is the official CARC description for code CO-24, maintained by X12 and last reviewed on March 1, 2026. It means the payer has a contract with the provider to pay a fixed amount per member per month for the patient’s care. The billed service falls within that prepaid arrangement and can’t be charged separately.

Is CO-24 a patient responsibility?

No. CO-24 carries the “CO” (Contractual Obligation) group code, meaning the denied amount is the provider’s responsibility to write off. CMS’s Medicare remittance guidance states that CO adjustments are “generally write-offs and are not billed to the patient.” Balance-billing a patient for a CO-24 amount may violate payer contracts and state consumer protection laws.

How do I resolve a CO-24 denial code?

Follow six steps: (1) review the ERA/EOB for CARC and RARC codes, (2) verify the patient’s capitation enrollment at the date of service, (3) check whether the service is carved out or bundled in your capitation contract, (4) redirect the claim to the correct payer or write off the amount, (5) check for modifier exceptions (GV/GW for hospice, Q0/Q1 for clinical trials), and (6) file an appeal within the payer-specific deadline if the denial is incorrect.

Can you appeal a CO-24 denial?

Yes, if the denied service was incorrectly flagged as capitated. Appeal-worthy scenarios include services carved out of the capitation contract, patients not enrolled in managed care at the date of service, and payer system errors. Deadlines vary: 120 days for Original Medicare, 60 days for Medicare Advantage payment disputes, and 90 to 180 days for commercial payers.

What is a CO-24 denial for Medicare?

A CO-24 Medicare denial typically happens when a claim goes to Original Medicare for a patient enrolled in a Medicare Advantage plan (Part C). Medicare Advantage replaces Original Medicare for most services, so claims must go to the private insurer managing Part C coverage. The one exception: hospice care, which Original Medicare still covers for MA patients.

What is the difference between CO-24 and CO-45?

CO-24 indicates a service is covered under a capitation agreement; the issue is the payment model. CO-45 indicates charges exceed the provider’s contracted fee schedule; the issue is the billed rate. Both carry the “CO” group code (contractual obligation), meaning the patient isn’t responsible in either case. They require completely different resolution approaches.

What are the most common mistakes that cause CO-24 denials?

Three mistakes account for most CO-24 denials: (1) not verifying whether the patient is enrolled in a capitated or managed care plan before delivering care, (2) submitting claims to the wrong payer, most commonly billing Original Medicare when the patient has Medicare Advantage, and (3) billing separately for services already included in the capitation agreement.

Who pays for capitation?

The managed care organization (MCO) or insurance payer pays the provider a fixed fee per enrolled patient per month, known as a PMPM (per member per month) payment. This covers a specified set of services regardless of how many times the patient is seen. The patient pays plan premiums, copays, and deductibles as required by their coverage.

How many people are enrolled in Medicare Advantage in 2026?

Over 35 million people are enrolled in Medicare Advantage plans as of February 2026, representing more than 54% of all eligible Medicare beneficiaries. That’s an increase of 1.1 million from February 2025. With more than half of Medicare patients now in managed care, capitation-related denials like CO-24 are showing up more frequently across all practice types and specialties.

Stop Losing Revenue to CO-24 Denials

The CO-24 denial code is one of the most preventable denials in medical billing. Verify eligibility before every visit. Know your capitation contracts. Train your billing team on managed care workflows. Flag capitated patients in your system before claims go out.

When denials do land on your desk, follow the six-step resolution process: review, verify, check contracts, redirect or write off, check for modifier exceptions, and appeal when the denial is wrong.

Managing denials internally takes time, specialized knowledge, and consistent follow-through that many practices struggle to maintain, especially as denial volumes keep climbing.

Let One O Seven RCM Handle Your Denials, So You Can Focus on Patient Care

One O Seven RCM is a full-service revenue cycle management company that specializes in denial management, claims resolution, and revenue recovery for healthcare providers across all specialties. Our team identifies denial patterns, including capitation-related denials like CO-24, and implements root-cause fixes that prevent recurrence.

Why providers choose One O Seven RCM:

• Medical billing services at 2.99% of collections, among the most competitive rates in the industry
• Provider credentialing at $99 per insurance, fast, accurate, and fully managed
• Dedicated denial management with one of the highest recovery rates in the market
• End-to-end revenue cycle management from patient eligibility to final payment posting

Request a Free Denial Analysis →