Denial code CO-243: Services not authorized by network provider
The service needed a referral or authorization from the patient's network provider.
At a glance
| Code | CO-243 (group CO, reason 243) |
| Who owes it | Contractual obligation: The provider must write this off. The patient cannot be billed for it. |
| Type | Prior authorization |
| Worth appealing? | Usually yes, once the cause is fixed |
How to fix it
- Get the referral from the primary care provider and resubmit.
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Start free for 14 daysFrequently asked questions
What does denial code CO-243 mean?
The service needed a referral or authorization from the patient's network provider.
How do I fix a CO-243 denial?
1. Get the referral from the primary care provider and resubmit.
Should I appeal a CO-243 denial?
Usually yes, or send a corrected claim. CO-243 denials are often recoverable once the cause is fixed. Check the payer's appeal deadline (often 60 to 180 days, 120 days for Medicare redeterminations).
Can I bill the patient for CO-243?
No. With group code CO the amount is not the patient's responsibility and must be written off unless it is overturned.
Plain-English summary for billing staff, not the official code text. See x12.org/codes for the official wording, and always follow the payer's own policy.