835 Denial Combination

CO-3

CO

Contractual Obligation · Service-Line Level Adjustment

Patient Responsibility

What This Combination Means

This combination appears when the payer is reporting a patient copayment amount using group code CO instead of the expected PR (Patient Responsibility) group code. The CO designation creates a technical inconsistency because copayments are patient financial obligations, not contractual provider write-offs. The amount represents a copayment the patient owes and should be billed accordingly.

Financial Responsibility

patient responsibility

The patient owes the copayment amount. Despite the CO group code, CARC 3 definitionally identifies a patient copayment obligation that can be billed to the patient.

N/A

Appeal Success

Immediate (patient billing)

Avg. Resolution

Easy

Difficulty

No

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-3 combination — not generic advice.

Not Appealable:Copayment amounts are patient financial obligations defined by the benefit plan and are not subject to appeal.
  1. 1

    Verify patient benefit plan copayment amount matches the adjustment posted

    Confirm this amount aligns with the copayment specified in the patient's insurance contract for this service type

  2. 2

    Bill the patient for the copayment amount shown

    Transfer the copayment to the patient's account balance regardless of the CO group code designation

  3. 3

    Document the group code discrepancy if it recurs with this payer

    Note the inconsistent use of CO for patient copayments for potential discussion with payer or EDI vendor to align future remittance coding

Specialty Context

How CO-3 typically presents across different practice types.

Dental

Common for routine preventive and restorative procedures where benefit plans specify fixed copayment amounts per visit or service category.

Medical

Standard for office visits, specialist consultations, urgent care, and other services with defined copayment requirements under the patient's benefit plan.

Behavioral Health

Routine for outpatient therapy sessions, psychiatric visits, and counseling services where copayments are collected per session.

Individual Code References

View the standalone definition for each code in this combination.

CARC 3

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Synthesized from official definitions — not from training data

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