CO-196 denial code
Claim denied based on the prior payer's coverage determination
How to fix it
Resolve the primary denial first. The secondary will generally not pay while the primary denial stands.
How to prevent it
Work primary denials before billing secondary; the secondary inherits the outcome.
In practice
A primary payer denies a service as not medically necessary. The practice bills the secondary hoping for a different view, and the secondary returns CO-196.
Secondary plans generally adopt the primary's coverage determination rather than conducting their own. The second claim was decided by the first payer's reasoning before it was ever reviewed.
The work belongs with the primary. Appeal there, obtain a corrected determination, and only then rebill the secondary with the revised remittance attached.
What sits behind it
The intuition that a second payer offers a second opinion is understandable and mostly wrong. Coordination rules position the secondary behind the primary, and most contracts explicitly condition payment on the primary having covered the service.
There are narrow exceptions worth knowing. Where the secondary's benefit is broader than the primary's, or where the plans use different coverage criteria for the same service, a secondary can pay what a primary declined — but this has to be checked rather than assumed.
Sequencing also protects the deadline. Secondary filing windows commonly run from the primary's adjudication date, so resolving the primary produces both a better claim and a fresh clock, whereas billing the secondary first wastes the attempt.
Related codes
Terms used here — Coordination of Benefits · Denial · Appeal
How we handle it — Denial Management · AR Management · Claims Management
Primary sources
The rules behind CO-196, 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-196
Occasionally, where its benefit is genuinely broader or it applies different coverage criteria to the same service. That has to be verified against the secondary's terms rather than assumed, because most contracts condition payment on the primary having covered the service.
Primary first, always. Resolving the primary produces a corrected adjudication to send the secondary and generally restarts the secondary filing window, which commonly runs from the primary's adjudication date rather than the date of service.
The corrected primary remittance showing the revised determination, with coordination of benefits data matching it at line level. A narrative explaining that the primary denial was wrong carries far less weight than the corrected adjudication itself.
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