Appealing a Medicaid CO-45 Denial
A Medicaid CO-45 denial (charge exceeds fee schedule) is one of the most common claim rejections behavioral health therapists face. This guide explains exactly what caused the denial and the most effective appeal strategy for behavioral health practices.
What this denial means
Your billed charge is higher than the maximum the payer allows for this service under the fee schedule. This is a contractual reduction — it is not a denial of the service, just a reduction to the contracted rate. No appeal is required unless you believe the fee schedule was applied incorrectly.
Your appeal strategy
Confirm the billed code was correct. If you believe the fee schedule rate was applied in error (wrong contract, wrong table year, out-of-network rate applied to an in-network claim), request the fee schedule documentation from the payer and compare against your contract. File a payment dispute with the contract reference if there is a discrepancy.
What Medicaid requires
30 calendar days (Level-1 appeal)
90 days from Level-1 denial
Medicaid rules vary substantially by state and managed-care organization (MCO). Under the ACA, states must cover mental health and SUD services as essential health benefits. State fair-hearing rights apply (42 CFR § 431.200). Federal MHPAEA does NOT apply to Medicaid — Medicaid is governed by separate parity rules rather than the federal MHPAEA standard (29 CFR § 2590.712). Specific appeal addresses depend on the MCO (Molina, Centene/WellCare, Aetna Better Health, etc.).
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Generate my appeal letter →Frequently asked questions
How long does Medicaid have to respond to a CO-45 appeal?
Under federal regulations, Medicaid must respond to a Level-1 internal appeal within 30 calendar days. State insurance law, including your state's prompt-payment statute, does not apply to this federal program — confirm the current response-window rules directly with the program administrator before filing. If you receive an adverse determination, you typically have 90 calendar days from the date of the Level-1 denial to request external review. Send the appeal via certified mail or through the payer's portal and keep documentation of the submission date. Note: these timelines are best-effort estimates — verify current deadlines directly with the payer.
Does MHPAEA apply to CO-45 denials?
No. Medicaid is not subject to the federal Mental Health Parity and Addiction Equity Act (MHPAEA) at all, so a parity argument does not apply to a CO-45 denial — or any denial — from this payer. Base your appeal on Medicaid's own coverage rules and appeal process. Medicaid rules vary substantially by state and managed-care organization (MCO). Under the ACA, states must cover mental health and SUD services as essential health benefits. State fair-hearing rights apply (42 CFR § 431.200). Federal MHPAEA does NOT apply to Medicaid — Medicaid is governed by separate parity rules rather than the federal MHPAEA standard (29 CFR § 2590.712). Specific appeal addresses depend on the MCO (Molina, Centene/WellCare, Aetna Better Health, etc.).
Can I appeal a CO-45 denial more than once?
Yes. Most payers, including Medicaid, allow at least two levels of internal appeal (Level-1 and Level-2 or "expedited" review). Keep copies of every appeal, submission confirmation, and payer response. After exhausting the managed care organization's (MCO) internal grievance and appeal process, you have the right to a state Medicaid fair hearing under 42 CFR 431.200. Your state insurance commissioner does not handle Medicaid appeals — use your state Medicaid agency's fair-hearing process instead.
What documentation do I need to appeal a CO-45 denial from Medicaid?
At minimum: the original Explanation of Benefits (EOB) or Remittance Advice (RA) showing the CO-45 denial, the original claim details (CPT code, date of service, NPI, charge amount), and any clinical documentation supporting medical necessity. Submit everything in one packet with a cover letter citing the specific denial code, the date of service, and the claim number.