CO-243: Services Not Authorized by Network Provider

What Does CO-243 Mean?

CO-243 means the provider is financially responsible because they failed to obtain the required prior authorization. The provider's contract with the payer typically requires prior auth for certain services, and the provider did not fulfill this obligation. The patient cannot be billed for this failure.

CARC 243 is an authorization denial. The payer has determined that the services rendered were not authorized by the patient's network or primary care provider. This can mean prior authorization was never obtained, the authorization expired before services were rendered, the authorization was for a different service than what was performed, or the patient did not get the required referral from their PCP. This code replaced the older deactivated CARC 38.

Unlike CARC 242 (which focuses on whether the provider is in-network), CARC 243 focuses on whether the specific service was approved. A provider can be fully in-network and still trigger this code if authorization was not obtained for the particular procedure or visit. The financial responsibility depends on who was responsible for obtaining the authorization — if the provider was contractually required to get prior auth and failed to do so (CO), the provider absorbs the cost. If the patient was required to get a referral (PR), the patient is responsible.

Retroactive authorization is often possible with strong clinical documentation supporting medical necessity. Many payers have specific timeframes for retroactive auth requests, and emergency situations typically have extended or waived auth requirements.

Common Causes

How to Resolve

Determine why authorization was missing, pursue retroactive authorization or referral if possible, resubmit with authorization information, or assign responsibility to the appropriate party.

1. Request retroactive authorization Submit a request for retroactive authorization with comprehensive clinical documentation proving medical necessity. Include the reason authorization was not obtained prospectively.
2. Check authorization records Verify that authorization was not actually obtained but missing from the claim. If an auth number exists, add it to the claim and resubmit.
3. Appeal or write off If retroactive auth is granted, resubmit. If denied, determine if an appeal is warranted based on emergency circumstances or medical necessity. Otherwise, write off the amount.

Common RARC Pairings

The RARC code tells you exactly what triggered the CO-243:

How to Prevent CO-243

• Implement a prior authorization verification process for all scheduled services before they are rendered
• Track authorization expiration dates and remaining authorized visits in your scheduling system
• Ensure the authorization number is attached to every claim before submission
• Train staff to verify authorization requirements before patient appointments
• Establish an urgent authorization process for services that cannot wait for standard approval

General Prevention

• Implement a robust prior authorization process that verifies authorization requirements before every scheduled service
• Track all active authorizations including expiration dates and remaining authorized visits to prevent lapses
• Ensure the correct authorization number is attached to every claim before submission
• Train scheduling and front-office staff to verify authorization status before appointments
• Establish a process for urgent or emergent authorization requests when services cannot wait for standard approval timelines

Also Filed As

The same CARC 243 may appear with different Group Codes:

Related Denial Codes