Appealing a Blue Cross Blue Shield (generic) CO-15 Denial
A Blue Cross Blue Shield (generic) CO-15 denial (authorization number missing or invalid) 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 cannot match the authorization number on your claim to a valid prior authorization in their system. This is different from CO-197 (no auth obtained) — here the auth may exist but the number is wrong, missing from the claim form, or expired.
Your appeal strategy
Pull the authorization number from your records and verify it matches exactly what appears on the claim. If it does, provide the authorization confirmation document with your appeal. If the payer issued the auth but cannot find it, request escalation to the authorization department and document all contact attempts.
What Blue Cross Blue Shield (generic) requires
30 calendar days (Level-1 appeal)
60 days from Level-1 denial
BCBS affiliates are independent licensees — appeal addresses, portals, and state parity rules vary by state plan. Look up the specific affiliate (e.g. BCBS of Illinois, BCBS of Michigan) for accurate address. The BCBS Federal Employee Program (FEP) has a separate appeals process.
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Generate my appeal letter →Frequently asked questions
How long does Blue Cross Blue Shield (generic) have to respond to a CO-15 appeal?
Under federal regulations and most state prompt-payment laws, Blue Cross Blue Shield (generic) 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. Note: these timelines are best-effort estimates — verify current deadlines directly with the payer.
Does MHPAEA apply to CO-15 denials?
CO-15 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-15 denial more than once?
Yes. Most payers, including Blue Cross Blue Shield (generic), 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-15 denial from Blue Cross Blue Shield (generic)?
At minimum: the original Explanation of Benefits (EOB) or Remittance Advice (RA) showing the CO-15 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.