Appealing an Aetna CO-97 Denial
An Aetna CO-97 denial (bundled / already adjudicated) 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
The payer says this service is included in another service that's already been billed and paid. In behavioral health, this most commonly happens when an E/M visit (99213/99214) and psychotherapy (90834/90837) are billed on the same day without the -25 modifier on the E/M code to establish that it is a separately identifiable service.
Your appeal strategy
Cite documentation establishing the services as separately identifiable — distinct CPT codes, a separate clinical purpose for each, and (when applicable) the -25 modifier on the E/M code. Reference CMS NCCI Edit Policy Chapter 11, which explicitly permits same-day E/M + psychotherapy when -25 is applied. If the modifier was present and the denial is still issued, request the specific NCCI edit being invoked.
What Aetna requires
P.O. Box 14463
Lexington, KY 40512
30 calendar days (Level-1 appeal)
60 days from Level-1 denial
1-860-754-2985
Aetna publishes MHPAEA comparative analyses on request; behavioral health benefits are administered through Aetna Behavioral Health. Document parity violation in detail — Aetna's internal process requires a specific MHPAEA flag in the appeal routing system.
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Generate my appeal letter →Frequently asked questions
How long does Aetna have to respond to a CO-97 appeal?
Under federal regulations and most state prompt-payment laws, Aetna must respond to a Level-1 internal appeal within 30 calendar days. If you receive an adverse determination, you typically have 60 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.
Does MHPAEA apply to CO-97 denials?
CO-97 denials are not directly tied to mental health parity protections in most cases — this code is a general adjudication rule that applies equally to all claim types. MHPAEA may still be relevant if the underlying reason for the denial differs for mental health vs. medical/surgical services. When in doubt, include a parity argument in your appeal.
Can I appeal a CO-97 denial more than once?
Yes. Most payers, including Aetna, allow at least two levels of internal appeal (Level-1 and Level-2 or "expedited" review). After exhausting internal appeals, you have the right to request an Independent Medical Review (IMR) or external review through your state insurance commissioner. Keep copies of every appeal, submission confirmation, and payer response.
What documentation do I need to appeal a CO-97 denial from Aetna?
At minimum: the original Explanation of Benefits (EOB) or Remittance Advice (RA) showing the CO-97 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.