CO-111 denial code
Not covered unless the provider accepts assignment
How to fix it
Confirm your participation status and assignment election with this payer.
How to prevent it
Maintain a current record of which payers you accept assignment with, per provider.
In practice
A non-participating provider bills a plan that pays only providers accepting assignment. The claim returns CO-111 and no payment reaches the practice.
Accepting assignment means agreeing to take the plan's allowed amount as payment in full and receive payment directly. A provider who has not made that election is outside the arrangement the plan is willing to pay into.
Confirm the participation and assignment status held for this provider with this payer, since it is frequently a record that was never updated after a change. Where the election genuinely was not made, the payment routes to the patient and the practice collects from them.
What sits behind it
Assignment status is a per-payer, per-provider election rather than a single practice-wide setting, and that is where the confusion usually starts. A provider can accept assignment with one plan and not another, and the record has to be right in each place.
Medicare draws a further distinction that trips practices moving into or out of participation. Participating providers accept assignment on all claims; non-participating providers may accept it claim by claim and are subject to limiting charge rules when they do not. The two positions have different billing consequences for the patient.
The workable control is a maintained record of participation and assignment status per provider per payer, reviewed when anyone joins, leaves or changes status. Without it this denial appears months after the change that caused it, by which time the filing window may be tight.
Related codes
Terms used here — Out-of-Network · Credentialing · Patient Responsibility
How we handle it — Provider Credentialing · Patient Collections · Denial Management
Primary sources
The rules behind CO-111, at the bodies that publish them.
- PECOS Medicare enrollment (opens in a new tab)
Centers for Medicare & Medicaid Services — Where Medicare provider enrollment is filed and maintained. Revalidation deadlines missed here stop payment outright.
- NPI Registry (NPPES) (opens in a new tab)
Centers for Medicare & Medicaid Services — Public lookup and management for National Provider Identifiers. A stale NPPES record is a quietly common cause of enrollment and claim rejections.
- Medicare Claims Processing Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — The operative manual for how Medicare claims must be coded, submitted, adjusted and appealed. When a payer policy and a vendor's advice disagree, this settles it.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-111
Agreeing to accept the plan's allowed amount as payment in full and to receive payment directly from the plan rather than through the patient. It is elected per payer and per provider, so a practice can hold different positions with different plans.
Generally not, which is why the record matters before claims are submitted rather than after. Where the payer's record is simply stale and the election was in fact made, correcting the enrolment record and requesting reprocessing is the route.
The patient receives the payment and the practice bills them, which makes CO-100 a frequent companion to this code. Knowing in advance which payers behave this way lets the practice decide whether to collect at the time of service.
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