Appealing an Anthem (BCBS) CO-29 Denial
An Anthem (BCBS) CO-29 denial (timely filing limit expired) 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 the claim was submitted after their filing deadline. Most commercial payers require claims within 90–365 days of the date of service; Medicaid and Medicare have their own windows.
Your appeal strategy
Appeal with documented proof that the claim was submitted on time — clearinghouse submission reports with timestamps are ideal. If late submission was caused by payer error (e.g. incorrect enrollment, address change not processed), document the cause and cite any applicable exceptions. For government programs, cite the exact regulatory exception you are invoking.
What Anthem (BCBS) requires
P.O. Box 60007
Los Angeles, CA 90060
30 calendar days (Level-1 appeal)
60 days from Level-1 denial
1-866-755-2680
Anthem (now Elevance Health) is a major BCBS licensee operating in ~14 states. File appeals to the state-specific Anthem entity; addresses vary by state. Behavioral health managed through Sydney Health / Anthem Behavioral Health.
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Generate my appeal letter →Frequently asked questions
How long does Anthem (BCBS) have to respond to a CO-29 appeal?
Under federal regulations and most state prompt-payment laws, Anthem (BCBS) 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-29 denials?
CO-29 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-29 denial more than once?
Yes. Most payers, including Anthem (BCBS), 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-29 denial from Anthem (BCBS)?
At minimum: the original Explanation of Benefits (EOB) or Remittance Advice (RA) showing the CO-29 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.