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CO-220Coding

How to Appeal CO-220 Denial: Code not in applicable fee schedule

The applicable fee schedule does not contain the billed procedure code. This guide explains what it means, why it happens, and exactly how to build a winning appeal.

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What Does CO-220 Mean?

The applicable fee schedule does not contain the billed procedure code.

Commonly seen in:

New CPT codesUnlisted codesHCPCS Level II

Step-by-Step Appeal Guide for CO-220

  1. 1

    Pull the original claim and identify every CPT/HCPCS code and modifier submitted

  2. 2

    Compare your coding to the CPT guidelines and payer-specific billing manual

  3. 3

    Gather the operative report, progress notes, or other documentation supporting your coding

  4. 4

    Draft a cover letter explaining the clinical rationale for the code/modifier combination

  5. 5

    Attach supporting documentation and resubmit within the payer's appeal deadline

Counter-Arguments to Use in Your Appeal

These are the strongest arguments medical billing professionals use to overturn CO-220 denials.

  • For unlisted codes, provide a letter of medical necessity and a comparable listed code

  • Reference the CMS crosswalk if this is a new code without a fee schedule yet

  • Request a gap fill price from the MAC/payer for new codes

  • Submit with a detailed description of the service and comparable code pricing

Regulations and Guidelines to Cite

Citing specific regulations strengthens your appeal and demonstrates you know your rights.

CMS fee schedule gap fill process
CMS HCPCS Level II updates
💡

Expert Tip for CO-220 Appeals

For new codes without fee schedule entries, attach a letter explaining the service and suggesting a comparable code for pricing. Many payers will manually price it.

Frequently Asked Questions

What is a CO-220 denial code?

The applicable fee schedule does not contain the billed procedure code.

Can I appeal a CO-220 denial?

Yes. All insurance denials are appealable. Follow the step-by-step guide above and submit your appeal before the payer's deadline, typically 180 days from the denial date.

What documentation do I need to appeal CO-220?

For a CO-220 denial, you typically need: the original denial letter/EOB, clinical documentation supporting the service, any prior authorization records, and a cover letter citing the relevant regulations listed above. The specific documents depend on why the denial was issued.

How long does a CO-220 appeal take?

Most payers are required to process standard appeals within 30–60 days. Expedited appeals (for urgent care) must be decided within 72 hours. Under ERISA, group health plans must provide an appeal decision within 60 days for pre-service and 60 days for post-service claims.

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