Prior Authorization
Definition
Prior authorization (PA) is a requirement by a health insurance payer that the provider obtain approval before delivering a specific service, procedure, or medication. The payer reviews clinical documentation to determine medical necessity before agreeing to cover the cost. Without PA, the claim is denied under CO-50 (not covered per policy) or CO-197 (precertification absent).
Why Prior Authorization Matters
Physicians submit an average of 45 PA requests per week. Staff spend 14 hours per week on PA paperwork. 92% of providers report PA delays patient care. PA denials account for a significant share of all claim denials. Missing or expired PA is one of the most common — and most preventable — denial causes in medical billing.
How Prior Authorization Works
The provider submits a PA request with clinical documentation to the payer before the service. The payer reviews the request against their coverage criteria. Standard review takes 5-15 business days; expedited review (for urgent cases) takes 24-72 hours. CMS rule CMS-0057-F requires payers to respond within 72 hours for expedited requests and 7 days for standard requests starting January 2026. If approved, the provider receives an authorization number to include on the claim. If denied, the provider can appeal with additional clinical documentation. See prior authorization rules.
Related Terms
Precertification — often used interchangeably with prior authorization. Medical necessity — the standard payers apply when reviewing PA requests. Authorization number — the reference number issued upon PA approval. Appeal process — the path to contest a PA denial.
Common Questions
What happens if I provide a service without prior authorization?
The claim is denied. You can submit a retroactive PA request (some payers allow this within 24-48 hours for emergencies), but most payers reject retroactive requests for non-urgent services. The provider absorbs the cost.
Altair helps billing teams resolve denials faster. 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.