Out-of-network denial codes
There is no single out-of-network denial code. Payers split the problem across several codes depending on what actually went wrong: PR-242 when the provider who delivered the care is outside the plan's network, CO-243 when the plan's gatekeeper - usually the primary care provider - never referred or authorized the visit, CO-256 when the managed care contract does not make the service payable to you, and OA-100 when an out-of-network claim was paid but the money went to the patient. The group code in front of the number decides whether the balance can be billed to the patient at all.
Also described as: non-participating provider; provider not in network; no referral from the PCP; paid to the member instead of the provider.
The 4 codes and what separates them
PR-242 - Services were not provided by network providers
The provider who delivered the service is outside the plan's network, and the plan limits coverage to it. The balance shifts to the patient unless a balance-billing protection applies.
Who pays: Patient, if not protected
CO-243 - Services were not authorized by the network or primary care provider
Your network status may be fine; the plan requires a referral or authorization from the patient's primary care provider and none was on file.
Who pays: Provider
CO-256 - The service is not payable under the managed care contract
The patient's managed care agreement does not make this service payable to you - typically because it is delegated to another entity or sits outside your contracted service categories.
Who pays: Another payer
OA-100 - Payment was made to the patient instead of the provider
Not a denial: the claim was paid, but to the patient rather than to you, because the plan pays members directly on out-of-network claims or did not recognise the assignment of benefits.
Who pays: Patient (already paid)
How to tell which one you have
Start with the group code and the remark codes on the line. A PR group code on 242 means the payer treated you as non-participating for this member, so check your participation status for the member's specific product on the date of service before accepting it - lapsed or mis-loaded participation is a common cause. A 243 is about the referral rather than your network status, so the fix is the referral record. A 256 is contractual, so it goes to your contracting or provider relations contact rather than back through claims. An OA-100 line carries a paid amount: the work is collecting from the patient, not appealing.
Frequently asked questions
- What is the denial code for out of network?
- The most common is PR-242, which means the service was not provided by a network provider and moves the balance to the patient. CO-243 is used when the plan's gatekeeper did not refer or authorize the service, and CO-256 when the managed care contract does not make the service payable to the provider. Read the group and remark codes together to tell which one applies.
- Can I bill the patient for an out-of-network denial?
- Only when the group code is PR and no balance-billing protection applies. The federal No Surprises Act bars balance billing for emergency services and for certain non-emergency care delivered by out-of-network clinicians at in-network facilities, and many states add their own protections. CO-243 and CO-256 carry a contractual group code, so those balances are not the patient's.
- Why did the insurance pay the patient instead of me?
- That posts as OA-100. Plans commonly pay the member directly on out-of-network claims, and some do so whenever an assignment of benefits is missing or not recognised. The claim was paid, so there is nothing to appeal - bill the patient for the amount they received, and make sure future claims carry a signed assignment of benefits.
Other denial reasons
Last reviewed .
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.