Authorization Number
Definition
An authorization number is a unique identifier assigned by a payer when prior authorization is approved. The number documents that a specific service is approved for coverage and is medically necessary according to the payer's clinical guidelines. This number must be included on the corresponding claim.
Why It Matters
An authorization number proves the service was pre-approved and should be paid. Omitting it from claims results in denials and revenue loss. Tracking authorization numbers ensures compliance with payer requirements and protects against later claims disputes. Expired authorization numbers cause claim rejections.
How It Works
Before delivering services that require prior authorization, you submit an authorization request to the payer with clinical justification. The payer reviews the request against medical necessity guidelines. If approved, the payer assigns a unique authorization number and specifies the authorized service, date range, and number of units covered. You must record this number and include it on the claim submission. When the claim is submitted with the correct authorization number, the payer recognizes the service as pre-approved and processes payment accordingly. Claims submitted without required authorization numbers are denied, often with CO-197 codes.
Related Terms
What happens if you bill without an authorization number when one is required?
The claim is typically denied with a CO-197 or similar code (missing authorization). The payer may demand repayment if the claim was paid in error. You may face an authorization penalty that reduces reimbursement. To avoid this, always verify authorization requirements before service delivery.
Is an authorization number the same as a referral?
No. A referral indicates a primary care provider sends a patient to a specialist. An authorization number is a specific payer approval that confirms the service is medically necessary and covered. A referral may be required to request authorization, but both are separate requirements.
See How Altair Tracks Authorization Numbers
Altair stores authorization numbers in patient records and flags claims missing required authorization before submission. See how it works.
This glossary is for informational purposes. Consult official billing guidelines and payer policies for definitive definitions. Last updated: 2026-04-06.