CO vs PR Denial Codes: What's the Difference?

Medical billing denial codes are grouped into categories that explain why a claim adjustment occurred. Two of the most common categories are CO (Contractual Obligation) and PR (Patient Responsibility) denial codes.

Understanding the difference between these code groups helps providers determine whether the balance should be written off or transferred to the patient.

What Are CO Denial Codes?

CO denial codes represent Contractual Obligation adjustments.

These adjustments occur when the payer reduces or denies payment based on contract terms, coverage rules, billing requirements, or reimbursement policies.

In most cases, the provider is responsible for the adjustment and cannot bill the patient for the denied amount.

Common examples include:

• CO-16 Missing Information

• CO-22 Coordination of Benefits

• CO-29 Timely Filing Limit Exceeded

• CO-45 Charge Exceeds Fee Schedule

• CO-97 Bundled Procedure

What Are PR Denial Codes?

PR denial codes represent Patient Responsibility adjustments.

These adjustments indicate that the patient is financially responsible for all or part of the claim.

The provider may collect the balance from the patient when allowed by payer rules and provider agreements.

Common examples include:

• PR-1 Deductible Amount

• PR-2 Coinsurance Amount

• PR-3 Copayment Amount

Key Differences Between CO and PR Codes

CO Denial CodesPR Denial CodesContractual obligationPatient responsibilityUsually cannot bill patientPatient may owe balanceRelated to payer policiesRelated to patient benefitsOften require claim correctionOften require patient payment

How To Determine Who Is Responsible

The denial code category is often the quickest way to determine financial responsibility.

If the code begins with CO, the adjustment is generally the provider's responsibility.

If the code begins with PR, the patient is generally responsible for the amount indicated on the claim.

Providers should always review payer contracts, explanation of benefits statements, and applicable billing regulations before transferring balances to patients.

Frequently Asked Questions

What does CO mean in medical billing?

CO stands for Contractual Obligation and indicates the provider is generally responsible for the adjustment.

What does PR mean in medical billing?

PR stands for Patient Responsibility and indicates the patient may owe part of the balance.

Can a provider bill a patient for a CO denial?

In most cases, no. CO adjustments are typically governed by payer contracts and reimbursement agreements.

Are deductibles considered PR codes?

Yes. Deductibles are commonly reported using PR denial codes.

Which is more common, CO or PR codes?

Both are common, but CO codes generally make up a larger portion of claim denials and payment adjustments.

Related Resources

• CO Denial Codes

• PR Denial Codes

• CO-16 Denial Code

• CO-45 Denial Code

• CO-97 Denial Code

• PR-1 Denial Code

• PR-2 Denial Code

• PR-3 Denial Code

Quick Summary

CO denial codes indicate provider responsibility based on payer contracts and reimbursement policies, while PR denial codes indicate patient responsibility for deductibles, copayments, coinsurance, or other covered balances.

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