What is the denial code for benefit maximum reached?

CO-119 means the patient has reached the benefit maximum for this service in the period, such as an annual visit limit, and PR-35 is the lifetime version. Both are about the patient's plan, so confirm the visit count with the payer and ask whether the plan offers a medical-necessity exception.

What is the denial code for too many units?

CO-151 is the usual code: the payer will not accept that many units of the code on one date. For Medicare and Medicaid this generally follows the Medically Unlikely Edit for the code. Check the MUE value and its adjudication indicator before deciding whether to appeal or correct the units.

Benefit limit and unit limit denial codes

Five codes say the payer has hit a ceiling, and the ceiling belongs to someone different each time. CO-119 means the patient used up the benefit allowed for this service in the period, such as an annual visit limit, and PR-35 that a lifetime maximum is exhausted. CO-151 means the payer will not accept this many units of the code on one date - Medically Unlikely Edits are the usual source. CO-198 means the claim went beyond what an authorization approved, and PI-222 that the provider's own contracted maximum for the period was reached across all of its patients.

Also described as: benefit maximum reached; visit limit met; lifetime maximum; units exceed the limit; MUE; frequency limit.

The 5 codes and what separates them

CO-119 - The benefit maximum for this period has been reached
The patient has used the full benefit the plan allows for this service in the period or episode, such as a yearly therapy visit cap.
Who pays: Provider
PR-35 - The lifetime benefit maximum has been reached
The patient has exhausted a lifetime maximum on this benefit.
Who pays: Patient
CO-151 - Payer deems the information does not support this many services
The units billed for the code on this date exceed what the payer will accept; for Medicare and many other payers this follows the Medically Unlikely Edits.
Who pays: Provider
CO-198 - The authorized limit for this service was exceeded
An authorization covered part of the service, but the claim went past its approved visits, units, or dates.
Who pays: Provider
PI-222 - The contracted maximum units for this period were exceeded
The provider has billed more units, hours, or days for the period than its contract with the payer allows, regardless of this patient.
Who pays: Provider

How to tell which one you have

Ask whose limit it is. CO-119 and PR-35 are the patient's benefit limits: verify the count against the plan's records, because visits with other providers count too, and ask whether the plan allows an exception for medical necessity. CO-151 is a per-code, per-day limit, so look up the MUE value for the code and whether its adjudication indicator allows an appeal with documentation. CO-198 is solved by extending the authorization. PI-222 is a contract matter between the provider and the payer, not something to rebill.

Frequently asked questions

What is the denial code for benefit maximum reached?: CO-119 means the patient has reached the benefit maximum for this service in the period, such as an annual visit limit, and PR-35 is the lifetime version. Both are about the patient's plan, so confirm the visit count with the payer and ask whether the plan offers a medical-necessity exception.
What is the denial code for too many units?: CO-151 is the usual code: the payer will not accept that many units of the code on one date. For Medicare and Medicaid this generally follows the Medically Unlikely Edit for the code. Check the MUE value and its adjudication indicator before deciding whether to appeal or correct the units.

Other denial reasons

Out of network No prior authorization Not medically necessary Service not covered Bundled or not paid separately Coding mismatch or invalid code Patient not eligible or coverage ended Another payer is responsible Missing information, duplicate, or late filing Provider not eligible or not credentialed Deductible, coinsurance, or copay Paid less than billed

Every denial code in one table

Last reviewed October 3, 2026.

These are original plain-English summaries written for reference, not the official X12 code descriptions. Payer handling of any code varies by contract - always verify against the remittance advice and your payer agreement before adjusting a claim.