CO-183: Referring Provider Not Authorized to Refer

What Does CO-183 Mean?

CO-183 indicates the payer considers the unauthorized referral to be the provider's responsibility. The claim is denied as a contractual write-off — the rendering provider cannot bill the patient for the denied amount. This is the most common pairing and usually means the referring provider's credentials or enrollment did not pass the payer's validation check.

CARC 183 appears on your remittance when the payer determines that the referring provider listed on the claim does not have the authority to refer the patient for the specific service that was billed. This is not a question about whether the service itself was appropriate or covered — the payer is specifically rejecting the referral source.

The most common triggers are credential-related. The referring provider's medical license may have expired, their NPI may be inactive, or they may not be enrolled with the payer's network. In managed care plans that require referrals from primary care physicians, the referring provider may not be designated as the patient's PCP or may lack the specialty qualifications the payer requires for that particular referral type. Another frequent cause is simply data entry error — the wrong NPI was entered on the claim, or the referring provider's information does not match the payer's records.

This denial creates a workflow bottleneck because you cannot simply fix a code and resubmit — you need to first determine whether the referring provider is actually eligible, and if not, whether a new referral from a different provider is needed. If the referring provider is eligible but the payer's records are outdated, you may need to coordinate between the provider and the payer to update enrollment information before resubmitting.

Common Causes

How to Resolve

Verify the referring provider's eligibility status with the payer, correct any information errors, and resubmit with valid referral documentation.

1. Check the referring provider's payer enrollment Verify that the referring provider is enrolled and active with the specific payer. If enrollment has lapsed, work with the referring provider to reinstate it before resubmitting.
2. Correct claim data and resubmit Fix any NPI, credential, or referring provider identification errors on the claim. Resubmit with the corrected referring provider information and valid referral documentation.
3. Obtain alternative referral if needed If the referring provider cannot be authorized, obtain a new referral from an eligible provider within the payer's network. Ensure the new referral covers the date of service.

Common RARC Pairings

The RARC code tells you exactly what triggered the CO-183:

How to Prevent CO-183

• Verify the referring provider's payer enrollment and credential status before processing claims with their referral
• Maintain a database of referring provider NPIs and enrollment status, updated regularly
• Implement automated referral validation that checks the referring provider's eligibility with the payer before claim submission
• Train staff on each payer's referral authorization requirements

General Prevention

• Verify the referring provider's eligibility and enrollment status with the payer before processing referrals
• Maintain an up-to-date database of referring provider credentials, NPI numbers, and payer enrollment status
• Implement automated referral management systems that flag unauthorized or non-credentialed referring providers before claim submission
• Conduct periodic audits of referral patterns to identify and address credential or enrollment gaps
• Train front-office and billing staff on referral authorization requirements specific to each payer

Also Filed As

The same CARC 183 may appear with different Group Codes:

Related Denial Codes