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Claim adjustment reason code

CO-242: Services not provided by network providers

CO-242 means: Services not provided by network/primary care providers. The plan pays only for its own network, and this provider was not in it for this service.

Read the group code before you act on this

242 is the reason. The CO in front of it is the group code, a separate field on the remittance, and it is the one that decides who owes the money: CO means contractual obligation — the payer says the amount is not billable to anybody, and it is written off unless the denial itself is overturned. You may not bill the patient. What the other group codes mean.

What causes CO-242?

Provider not contracted with this plan, as opposed to not contracted with this payer
Contract in place with the payer but not with the specific product the patient holds
Credentialing complete but the effective date after the service
Patient in a narrow-network or exchange product the practice does not participate in

How do you fix a CO-242 denial?

Confirm participation for the specific plan and product, not just the payer name. A contract with the payer does not mean every one of its plans has you in network.
Check the contract effective date against the date of service.
Where participation exists and the payer’s file is wrong, escalate to provider relations with the contract — and ask for reprocessing of every affected claim, not just this one.
Where the practice genuinely is out of network, check what the patient was told before the visit before any balance moves.

Can CO-242 be prevented?

Verify plan-level participation at eligibility. A payer contract does not mean every product under that payer’s name.

A denial like this one is the recurring cost that medical billing outsourcing is built to take off your desk — a dedicated seat working the queue instead of it waiting for whoever has a free hour.

Who does this work

A credentialing & enrollment seat at $2,200 per seat per month works this queue full time, during your business hours, inside your own system. Every call is logged with the payer reference number and the outcome, and every Friday you get it in writing.

What that seat does →

Check the date behind it, free

Denials in this family are usually a calendar problem wearing a coding costume: a revalidation that lapsed, an enrollment that deactivated, an attestation that expired. CMS publishes every provider’s revalidation due date free.

Look up an NPI → · What deactivation costs

Codes worked the same way

CO-242 is fixed in credentialing, not on the claim. So are these, which is why a queue sorted by recovery route moves faster than one sorted by code number — the same person, in the same system, with the same evidence to hand, clears all of them in one pass.

CO-B7 — Provider not eligible that day
CO-185 — Rendering provider not eligible
CO-8 — Procedure and provider type disagree
CO-107 — Qualifying claim not linked
CO-183 — Referring provider not eligible
CO-184 — Ordering provider not eligible

Specialties that name this among their costliest

These are specialties whose own worst denials include one of this kind. The line under each is the denial they name, quoted from their page so you can see what the link is based on.

Pediatrics
Newborn claims denied because the baby was never added to the policy inside the enrollment window
Pulmonology and Critical Care
Sleep study interpretation billed without the qualifying supervision or credentials

What leaving it costs

Working a denied claim costs $57.23 per denied claim in administrative time (source) — before any of it is recovered, and whether or not it ever is.

Payers ultimately pay roughly 90% of claims even while using an initial denial to slow payment (source), so the reason one sits is rarely that nobody knows how to work it. Put your own denial count in.

Questions

What does denial code CO-242 mean?

Services not provided by network/primary care providers. In plain terms: The plan pays only for its own network, and this provider was not in it for this service.

What causes CO-242?

Provider not contracted with this plan, as opposed to not contracted with this payer. Contract in place with the payer but not with the specific product the patient holds. Credentialing complete but the effective date after the service. Patient in a narrow-network or exchange product the practice does not participate in.

How do you fix a CO-242 denial?

Confirm participation for the specific plan and product, not just the payer name. A contract with the payer does not mean every one of its plans has you in network.. Check the contract effective date against the date of service.. Where participation exists and the payer’s file is wrong, escalate to provider relations with the contract — and ask for reprocessing of every affected claim, not just this one.. Where the practice genuinely is out of network, check what the patient was told before the visit before any balance moves..

Can CO-242 be prevented?

Verify plan-level participation at eligibility. A payer contract does not mean every product under that payer’s name.

Is CO-242 the same as PR-242?

Same reason, different group code. The number 242 is the reason: The plan pays only for its own network, and this provider was not in it for this service. The prefix says who carries the amount. CO means contractual obligation — the payer says the amount is not billable to anybody, and it is written off unless the denial itself is overturned. PR-242 is the same reason assigned to patient responsibility — the payer says the amount is owed by the patient, and it is billed to them. Read the prefix before the number: it decides whether you appeal, write off, or bill the patient.

What about the codes next to CO-242?

CO-241 and CO-243 are separate codes and this site does not yet cover them. The authoritative list is the X12 Claim Adjustment Reason Codes at x12.org/codes/claim-adjustment-reason-codes; a code is only described here once its official text, causes and fix have been written and checked.

Code descriptions are the standard X12 claim adjustment reason and remittance advice remark code text. Payer policies differ, and the payer’s own coverage policy governs any individual claim. This page is working guidance, not legal or clinical advice.

Last updated 2026-09-14. This is operational guidance drawn from payer remittance practice, not legal, coding or reimbursement advice. Payer-specific rules vary and change; confirm against the payer’s own policy before acting on a specific claim.

Written by Ibtesam Asif · Last updated 2026-09-14

Code descriptions are the standard published text. Everything after them is operational guidance on how the work is done, and payer policy governs any individual claim.

Other denial codes

Next step

Is CO-242 one of the denials costing you most?

Send a ninety-day denial report and an aged AR summary, with no patient identifiers. Within two working days you get a written summary of which denial reasons are costing you most and what is recoverable.

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Or write to ops@softhomeglobal.com