CO-242 denial code
Services not provided by network or primary care providers
How to fix it
Verify network status for the specific plan, not just the carrier. Appeal where no in-network provider was available.
How to prevent it
Verify network participation at the plan level during eligibility checks; carrier-level participation is not sufficient.
In practice
A patient is seen by a specialist whose practice participates with the carrier. The claim returns CO-242: services not provided by network providers.
The practice does participate with the carrier — but not with this specific plan. Carriers operate many networks, and participation in one does not imply participation in another, particularly for narrow-network and marketplace products.
Where an in-network provider was genuinely unavailable, a network-adequacy appeal is the route. Where the practice simply is not in this plan's network, the balance follows the plan's out-of-network rules, and what may be billed to the patient depends on whether the No Surprises Act applies.
What sits behind it
The distinction that causes most CO-242 is carrier-level versus plan-level participation. An eligibility check that confirms the patient has coverage with a carrier the practice participates with answers a question that is not the one the claim depends on.
Narrow networks make this materially worse. Marketplace and employer plans increasingly build restricted panels from a subset of the carrier's contracted providers, so a practice can be in-network for the carrier's flagship product and out for its narrow one, with no change in contract status.
The patient exposure is the part that needs handling before service rather than after. Out-of-network care changes cost-sharing substantially, and for emergency care and certain facility-based services the No Surprises Act limits what may be billed regardless of network status. A patient who learns their specialist was out of network from a bill has been failed at registration.
Related codes
Terms used here — Out-of-Network · Eligibility Verification · Patient Responsibility
How we handle it — Eligibility Verification · Provider Credentialing · Patient Collections
Primary sources
The rules behind CO-242, at the bodies that publish them.
- No Surprises Act guidance (opens in a new tab)
Centers for Medicare & Medicaid Services — Balance billing restrictions, good faith estimates and the independent dispute resolution process — all of which change what a practice may bill a patient.
- 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.
- 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.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-242
Because participation is per plan, not per carrier. Carriers operate multiple networks, and narrow-network and marketplace products are frequently built from a subset of contracted providers. A practice can be in-network for one product and out for another with no change in contract.
Yes, where no in-network provider was reasonably available — a network-adequacy argument. Also where the network status on file is simply wrong, which happens after contract changes that the payer's directory has not caught up with.
It depends on the plan's out-of-network benefit and on whether the No Surprises Act applies. For emergency care and certain facility-based services it limits balance billing regardless of network status. Where it does not apply, the plan's out-of-network cost-sharing governs.
Verify network participation at the plan level during eligibility checks, not at the carrier level. That single change removes most of this denial, and it is also what lets you tell a patient their cost before the visit rather than after.
Find out what your denials are costing you
A free billing audit reviews your denial rate, AR aging and clean claim rate against industry benchmarks. Takes about two minutes to request. No sales pitch.
No setup fees · You pay when we collect · Pricing from 3% of net collections