Loop 2300 REF/FL 63 A-C | Medicare Billing: CMS-1450 & 837I

Use when a treatment authorization code is issued.

Table 26: Loop 2300 REF/FL 63 A-C Fields
Treatment Authorization Code for Primary, Secondary, and Tertiary	Source
Enter an authorization or referral number when the services on the claim are either preauthorized or involve a referral.	Contact the payer for any required authorization codes.

When a Quality Improvement Organization (QIO) does a review, Medicare requires the treatment authorization code for all approved admissions services for outpatient preadmission, pre-procedure, or home IV therapy services.