CARC CO-45Humana

Humana CO-45 Fee Variance Payment Dispute

Charge exceeds fee schedule / contracted rate. Copy-paste appeal letter with documented overturn rate and attachment checklist for Humana.

CARC
CO-45
Denial code
Typical window
180 days
Verify on your EOB
Overturn
Qualitative
With documentation
Filing Type
Formal Appeal
Clinical dispute

Verify before filing

Filing deadlines, appeal addresses, and policy criteria in this template reflect typical payer behavior at publication. Humana updates policies frequently and plan-level rules vary by employer group, state, and line of business. Always cross-check the specific deadline and filing address on your EOB, and confirm current Humanamedical-policy language through the payer’s provider portal before submitting an appeal. Overturn-rate language below reflects AAPC-reviewer consensus, not payer-published statistics.

When to use this template

Most Humana CO-45 adjustments are valid contractual write-offs and should not be appealed. Investigate only when the variance is unexpectedly large, when the same CPT is paid different amounts on different claims, or when out-of-network fee schedules are applied to in-network claims.

Attachment checklist

  • Provider contract excerpt with contracted rate
  • EOBs for disputed claims
  • Fee-schedule summary

Missing any one of these is the single largest cause of appeal denials. Build a pre-filing checklist before you submit.

Copy-paste letter template

Swap in your patient details at every [bracketed field]. Attach the documentation listed above. Submit within 180 days of the original adjudication.

Humana / CO-45 appeal template~270 words
[Payment Dispute - Not a Clinical Appeal]

[Practice Letterhead]
[Date]

Humana Provider Relations / Contract Management

Re: Payment Dispute - CO-45 Fee Variance
Provider: [Practice Name, NPI, TIN]
Contract: [Contract ID / Effective Date]
Dispute Period: [Date range]
CPT Codes Affected: [List]

Dear Provider Relations:

We are disputing the allowed amounts on the following claims where the CO-45 contractual adjustment appears inconsistent with our contracted rate with Humana.

Contracted rate per contract dated [date]: CPT [X] = $[Y] allowable.

Disputed claims:

1. Claim [#], DOS [date], Member [ID]: Allowed $[A] (expected $[Y], variance $[A-Y])
2. [Repeat for each outlier claim]

Root-cause analysis:
[Identify the root cause, e.g. "Out-of-network fee schedule applied despite in-network status on the EOB"; "Case-rate contract not applied; claim paid per-procedure"; "Fee schedule not updated after contract renegotiation effective [date]"]

Documentation attached:
1. Provider contract excerpt showing contracted rate for the CPT
2. EOBs for all disputed claims
3. Network-status verification from Humana provider enrollment

We respectfully request review and reprocessing of these claims at the correct contracted rate.

Sincerely,
[Practice Administrator / Billing Manager Name]
[Practice Name]
[NPI, TIN]
[Contact phone and email]
Pro tip

Investigate only when the CO-45 variance is unusually large or inconsistent across claims. Routine CO-45 adjustments are valid contractual write-offs and should not be appealed.

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FAQ

Common questions on this template

How long do I have to file a CO-45 appeal with Humana?

180 days from the initial adjudication date for most Humana plans. Corrected claims (for administrative fixes like missing modifiers or auth numbers) have a different and usually longer window. Always confirm the specific deadline on the EOB for your claim.

What is the typical overturn rate for this denial type?

Moderate to high when a documented contract-rate mismatch exists. Success depends heavily on documentation completeness and whether the clinical criteria in Humana's medical policy are matched point-by-point in the appeal.

Should I file this as a corrected claim or a formal appeal?

CO-45 denials are usually formal clinical appeals. The template below follows the formal-appeal structure. Use a corrected claim only if the fix is administrative (a missing modifier, wrong NPI) rather than clinical.

Can I reuse this template for other payers?

The structure works for any payer, but the filing address, deadline, and policy references are specific to Humana. Check our other templates for payer-specific versions; we have 50+ payer/code combinations in the directory.

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