CO-242 means the patient's plan only covers this service when it comes from an in-network provider or their assigned primary care provider, and your practice is not one for this patient. Check the patient's network and PCP assignment and whether a referral or exception applies.
The official wording
The X12 Claim Adjustment Reason Code list defines 242 as: "Services not provided by network/primary care providers."
The letters in front are the group code. CO means contractual obligation (the provider absorbs it), PR means patient responsibility, and OA is other adjustment. The same reason code can come with different group codes, so always read both.
Common causes
- HMO or EPO plans that have no out-of-network benefit.
- Medicaid managed care with an assigned PCP.
- The payer's network file does not show your provider as in network.
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How to handle it
- Check your network status with that specific plan and product.
- Check the patient's PCP assignment and whether a referral was required.
- If network status is wrong, send proof of participation and ask for reprocessing. If it was an emergency, appeal under the plan's emergency rules.
One claim from an out-of-network provider
A patient with an HMO plan sees your specialist. Your provider is in network for the payer's PPO plans but not for its HMO.
| Item | On the claim | What it means |
|---|---|---|
| Plan | HMO, no out-of-network benefit | Only in-network providers are paid |
| Provider status | In network for PPO only | Not in this plan's network |
| Remittance | CO-242 | Service not by a network provider |
| Fix | Check if an exception or continuity of care applies | Otherwise write off or follow your policy |
Being 'in network with the payer' is not enough. You must be in network for the patient's specific plan.
When you can still get paid
CO-242 is hard to overturn, but these situations often win.
| Situation | What to send | Notes |
|---|---|---|
| Emergency care | Records showing it was an emergency | No Surprises Act protections may apply |
| Network adequacy gap | Proof no in-network specialist was available nearby | Ask for a single-case agreement |
| Continuity of care | Proof the patient was in active treatment before a network change | Many plans allow a transition period |
| Payer's network file is wrong | Your contract and effective date | Ask the payer to fix the file, then reprocess |
Always check network status for the exact plan when you schedule the patient.
How to fix CO-242
- Confirm the patient's exact plan and your network status for that plan.
- If the payer's network file is wrong, send your contract and ask for a reprocess.
- If it was an emergency or no in-network provider was available, appeal with proof.
- If none apply, write it off (CO) or follow your financial policy if the group code is PR.
- Next time, check network status at scheduling and get a single-case agreement first.
CO-242 checklist
- ☐ Network status checked for the patient's exact plan, not just the payer.
- ☐ PCP assignment checked for HMO and Medicaid managed care.
- ☐ Single-case agreement in place before out-of-network care.
- ☐ Payer network file matches your contracts.
Questions people ask about CO-242
Can I bill the patient for CO-242?
Check the group code and your state's balance billing rules. Federal and state surprise billing rules limit billing in many emergency and facility situations.
How is CO-242 different from CO-288?
CO-242 is about network or PCP status. CO-288 means a required referral was missing.
Can I bill the patient for CO-242?
Usually not with a CO group code. With PR, the plan says the patient owes it, but check your state's rules.
What is a single-case agreement?
A one-time contract with the payer to treat one patient as in network, usually when no in-network provider can do the service.
Does the No Surprises Act apply to CO-242?
For emergency care and some care at in-network facilities, yes. It limits what the patient can be billed.
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PR-1 · PR-2 · PR-3 · CO-4 · CO-5 · CO-11 · CO-15 · CO-16 · OA-18 · CO-22 · OA-23 · CO-24 · CO-26 · CO-27 · CO-29 · CO-31 · CO-45 · CO-49 · CO-50 · CO-59 · PR-96 · CO-97 · CO-109 · CO-119 · CO-129 · CO-140 · CO-146 · CO-151 · CO-167 · CO-170 · CO-181 · CO-185 · CO-197 · CO-198 · PR-204 · CO-234 · CO-236 · CO-242 · CO-252 · CO-253 · CO-288 · CO-A1 · CO-B7 · MA130 · N130 · N23 · N290
Timely filing limits by payer: Cigna timely filing limit · HealthSpring timely filing limit · Aetna timely filing limit · UnitedHealthcare timely filing limit · Humana timely filing limit · corrected claim timely filing limits
Sources: X12 Claim Adjustment Reason Code list (242), read October 12, 2026; CMS Medicare guidance where Medicare rules are mentioned. Last reviewed October 12, 2026. General information, not coding or legal advice. Payer rules differ, so check the remark code and the payer's own policy.