Prior Authorization Basics: What Every Biller Needs to Know
Prior authorization failures are a leading cause of claim denials and delayed care. This complete guide covers the auth process, common pitfalls, and how to manage it efficiently.
What Is Prior Authorization?
Prior authorization (also called prior approval, pre-authorization, or pre-cert) is a payer requirement that a provider must obtain approval BEFORE delivering a specific service. Without it, the claim will typically be denied.
Prior authorization is not a guarantee of payment — it is a clinical coverage determination. Even with an auth, the claim can still deny if billing errors exist or if the service delivered differs from what was authorized.
What Commonly Requires Prior Authorization?
- Elective surgical procedures (orthopedic, spine, cardiac)
- High-cost imaging (MRI, CT, PET scans)
- Specialty medications and biologics
- Inpatient admissions (except emergencies)
- Durable medical equipment above certain thresholds
- Mental health and substance use disorder treatment beyond visit limits
- Home health services
- Physical, occupational, and speech therapy after initial visits
- Genetic testing and molecular diagnostics
- Outpatient infusions
The Prior Authorization Workflow
- Identify whether auth is required — check payer's prior auth list. Never assume last year's list is current.
- Gather clinical documentation — diagnosis codes, procedure codes, clinical notes demonstrating medical necessity.
- Submit the authorization request — via payer portal, phone, or EDI. Document the request date and reference number.
- Receive the determination — approval, denial, or request for additional information. Typical turnaround: 1-3 business days.
- Document the authorization number — record it in the patient account. Attach it to the claim when billing.
- Confirm date range and service specificity — auth is only valid for authorized CPT codes, dates, and quantity.
- Bill with auth on the claim — include the authorization number in Box 23 on CMS-1500.
Common Prior Authorization Pitfalls
| Pitfall | Consequence | Prevention |
|---|---|---|
| Auth expired before service | Claim denied — outside auth window | Track auth expiration dates; extend if needed |
| Wrong procedure code authorized | Claim denied — unauthorized procedure | Confirm CPT codes match exactly before scheduling |
| Auth for wrong facility | Claim denied — site of service mismatch | Verify facility-specific auth requirements |
| Auth not attached to claim | Claim denied — no auth on file | Always include auth number in billing field |
| Retroactive authorization attempted | Often not possible — revenue lost | Never assume retroactive auth will be granted |
Key Takeaway
Prior authorization is a process management challenge as much as a clinical one. Track every auth request, document every determination, and never assume a service is covered without verification.
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