CO-101 denial code
Predetermination: anticipated payment upon completion of services
How to fix it
No action beyond confirming the eventual claim adjudicates as predicted.
How to prevent it
Predeterminations are not guarantees of payment; verify benefits independently.
In practice
A practice submits a predetermination for a costly elective procedure to establish what the plan will pay. The response comes back carrying CO-101, and it lands in the denial queue.
Nothing was denied. A predetermination is a question, not a claim, and CO-101 is the plan's way of saying it has answered the question rather than adjudicated a service.
The value of the response is planning: it tells you the anticipated payment so the patient can be counselled accurately. The actual claim still has to be submitted after the service, and it will adjudicate on its own facts.
What sits behind it
The crucial limitation is that a predetermination is not a guarantee. It reflects the plan's view based on the information supplied at that moment, and eligibility can lapse, benefits can exhaust and coverage terms can change between the estimate and the service.
It is also distinct from prior authorisation, and confusing the two is a costly error. Authorisation is a condition of payment; a predetermination is an estimate. Obtaining a predetermination where authorisation was required leaves the service unauthorised and the claim exposed.
Used properly, these are most valuable for high-cost elective work where the patient's financial exposure is the deciding factor. Sharing the predetermined amount before scheduling gives the patient a real number, which is better service and produces fewer disputed balances afterwards.
Related codes
Terms used here — Prior Authorization · Eligibility Verification · Patient Responsibility
How we handle it — Prior Authorization · Eligibility Verification · Patient Support
Primary sources
The rules behind CO-101, at the bodies that publish them.
- Medicare Coverage Database (LCD/NCD) (opens in a new tab)
Centers for Medicare & Medicaid Services — Searchable national and local coverage determinations. The direct answer to whether a diagnosis supports medical necessity for a given procedure.
- Medicare Benefit Policy Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — What Medicare covers and under what conditions, as distinct from how a claim is processed. The starting point for any coverage or medical necessity question.
- Advance Beneficiary Notice of Noncoverage (ABN) (opens in a new tab)
Centers for Medicare & Medicaid Services — The form and the rules for issuing it. Whether a non-covered service can be billed to the patient usually turns on whether a valid ABN was obtained beforehand.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-101
No. It reflects the plan's view based on the information available when it was issued, and coverage can change before the service. Eligibility may lapse, benefits may exhaust, and plan terms may be amended, any of which changes the outcome of the eventual claim.
No, and treating them as interchangeable is expensive. Authorisation is a condition of payment that must be obtained where required. A predetermination is an estimate with no such force, so obtaining one where authorisation was required leaves the service unauthorised.
No. It indicates a predetermination response rather than an adjudicated claim, so there is nothing to appeal. Route these out of the denial queue and use the estimate to counsel the patient before the service is scheduled.
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