835 Denial Combination

CO-5

CO

Contractual Obligation · Service-Line Level Adjustment

Coding Error

What This Combination Means

The billed procedure code does not match the place of service submitted on the claim, indicating a coding mismatch. The payer is adjusting the claim under contractual terms, requiring the provider to write off the amount rather than rebill the patient. The provider must identify whether the procedure code or place of service was coded incorrectly and submit a corrected claim if appropriate.

Financial Responsibility

provider writeoff

The provider must write off the adjusted amount due to contractual obligation. The patient cannot be billed for this coding inconsistency.

N/A

Appeal Success

7-14 days (corrected claim)

Avg. Resolution

Medium

Difficulty

No

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-5 combination — not generic advice.

Not Appealable:This is a contractual adjustment for a coding error, not a medical necessity or coverage determination, making it non-appealable.
  1. 1

    Compare the billed procedure code against the place of service code on the original claim

    Identify whether the procedure code is appropriate for the documented service location or if the place of service code was entered incorrectly

  2. 2

    Verify the correct place of service using CMS Place of Service code guidelines

    Confirm which place of service code accurately reflects where the service was performed (e.g., office, hospital outpatient, ambulatory surgical center)

  3. 3

    File a corrected claim with the accurate procedure code or corrected place of service code

    Use the appropriate claim correction mechanism (frequency code 7) to resubmit with the coding error resolved

Specialty Context

How CO-5 typically presents across different practice types.

Dental

Common when procedures like surgical extractions are billed with office place of service instead of ambulatory surgical center, or when hospital-based dental procedures use incorrect facility codes.

Medical

Frequently occurs with procedures restricted to specific settings (e.g., major surgeries billed with office POS, observation services with wrong facility type, or procedures requiring ASC/hospital setting billed as office visits).

Behavioral Health

May appear when psychotherapy codes are billed with incompatible place of service (e.g., telehealth procedures without appropriate POS 02, or intensive outpatient services billed as standard office visits).

Individual Code References

View the standalone definition for each code in this combination.

CARC 5

Medicare Contractor Guidance for CARC 5

Noridian

Place of service is not consistent with HCPC billed

How to Prevent CARC 5 Denials

  • ✓

    Verify prior to billing that the correct place of service for the HCPC provided is on the claim. The place of service for DMEPOS claims is considered the location where a beneficiary will primarily use the DMEPOS item.

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Synthesized from official definitions — not from training data

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