CO-119 Denial — How to Appeal for Behavioral Health
CO-119 (benefit maximum reached) 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-119 means
The payer is saying the patient has hit the maximum number of visits, days, or dollar amount allowed for this benefit under their plan. For mental health services, benefit maximums are frequently the most direct form of MHPAEA parity violation.
MHPAEA Mental Health Parity Argument
MHPAEA (29 CFR § 2590.712(c)) prohibits visit, day, or dollar limits on mental health or SUD benefits that are more restrictive than those applied to medical/surgical benefits — if a plan covers unlimited outpatient medical visits but caps therapy at 30 sessions, that is a per-se parity violation. CAA 2021 § 203 separately requires the plan to produce a written comparative analysis; that statutory duty was unaffected by the 2025 federal non-enforcement of the 2024 Final Rule.
Request your payer's written Non-Quantitative Treatment Limitation (NQTL) comparative analysis. They are required to provide it under CAA 2021 § 203.
Appeal strategy for CO-119
Determine whether the patient's plan imposes a visit or day limit on mental health services that does not apply to comparable medical/surgical outpatient services. If the limit is more restrictive for mental health, this is a textbook MHPAEA violation. Request the payer's comparative analysis document for mental health vs. medical/surgical benefit limitations.
CPT codes commonly denied with CO-119
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What does CO-119 mean on a behavioral health claim?
The payer is saying the patient has hit the maximum number of visits, days, or dollar amount allowed for this benefit under their plan. For mental health services, benefit maximums are frequently the most direct form of MHPAEA parity violation.
How do I appeal a CO-119 denial?
Determine whether the patient's plan imposes a visit or day limit on mental health services that does not apply to comparable medical/surgical outpatient services. If the limit is more restrictive for mental health, this is a textbook MHPAEA violation. Request the payer's comparative analysis document for mental health vs. medical/surgical benefit limitations.
Does MHPAEA apply to CO-119 denials?
Yes. MHPAEA (29 CFR § 2590.712(c)) prohibits visit, day, or dollar limits on mental health or SUD benefits that are more restrictive than those applied to medical/surgical benefits — if a plan covers unlimited outpatient medical visits but caps therapy at 30 sessions, that is a per-se parity violation. CAA 2021 § 203 separately requires the plan to produce a written comparative analysis; that statutory duty was unaffected by the 2025 federal non-enforcement of the 2024 Final Rule. Request the payer's written Non-Quantitative Treatment Limitation (NQTL) comparative analysis under CAA 2021 § 203 — that statutory disclosure duty applies regardless of the 2025 federal non-enforcement of the 2024 Final Rule.
Which insurers most commonly issue a CO-119 denial?
All major commercial payers — Aetna, Cigna, Anthem, UnitedHealthcare, Humana, and BCBS plans — use CO-119. 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.