CO-22 Denial — How to Appeal for Behavioral Health
CO-22 (coordination of benefits) is one of the most common insurance denial codes behavioral health therapists encounter. This guide explains what triggered the denial and the most effective appeal strategy across all major payers.
What CO-22 means
The payer believes another insurer should pay first. This triggers when a patient has multiple insurance plans and the primary/secondary sequence was not established or was submitted out of order.
Appeal strategy for CO-22
Verify the patient's COB information and confirm which plan is primary. Submit the EOB from the primary payer with the secondary claim. If your payer is primary but coded the claim as secondary, provide the COB letter or member insurance card showing your payer's priority status.
CPT codes commonly denied with CO-22
Appeal CO-22 by payer
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What does CO-22 mean on a behavioral health claim?
The payer believes another insurer should pay first. This triggers when a patient has multiple insurance plans and the primary/secondary sequence was not established or was submitted out of order.
How do I appeal a CO-22 denial?
Verify the patient's COB information and confirm which plan is primary. Submit the EOB from the primary payer with the secondary claim. If your payer is primary but coded the claim as secondary, provide the COB letter or member insurance card showing your payer's priority status.
Does MHPAEA apply to CO-22 denials?
CO-22 is a general adjudication code that typically applies equally to all claim types. MHPAEA may still be relevant if the payer applies the underlying rule differently to mental health services than to comparable medical/surgical services.
Which insurers most commonly issue a CO-22 denial?
All major commercial payers — Aetna, Cigna, Anthem, UnitedHealthcare, Humana, and BCBS plans — use CO-22. Government programs (Medicare, Medicaid, TRICARE) also issue this code. The appeal strategy is similar across payers, but deadlines and submission addresses vary. Select your payer from the list below for payer-specific instructions.