Prior authorization (prior auth, PA) is your insurer’s rule that certain drugs, imaging, surgeries, or durable equipment need approval before they are covered. UnitedHealthcare, Anthem, Aetna, Cigna, Kaiser, and Medicare Advantage plans all use some form of it. Skipping the step can leave you with a full retail bill even when the doctor is in-network.
This guide covers who starts the request, timelines, denials, and how PA ties to formularies and networks.
What prior auth is (and is not)
| Prior authorization | Referral | Precertification (wording varies) | |
|---|---|---|---|
| Main question | “Is this service/drug medically necessary under the plan?” | “May this specialist see you?” (common in HMOs) | Often similar to PA for hospital stays |
| Who usually files | Prescriber or facility with the plan | Primary care → specialist | Hospital or insurer workflows |
| Failure mode | Claim denied; you may owe retail or full allowed amount | Out-of-network or noncovered specialist visit | Stay or procedure not covered as expected |
PA is separate from your deductible and coinsurance. Approval means “eligible for coverage under plan rules,” not “$0 bill.”
Where you will see it most
- Brand-name or specialty drugs on a prescription formulary (non-formulary asks are often formulary exceptions, not plain PA). Why specialty coinsurance jumps: Specialty drug tiers
- Advanced imaging (MRI, CT) and some surgeries
- Certain durable medical equipment
- Non-emergency out-of-network requests on tighter networks
Retail pharmacies (CVS, Walgreens, independent) often learn about a drug PA when the claim rejects at the counter. The fix is usually the prescriber’s office submitting clinical notes to the pharmacy benefit manager (PBM) or plan—not you arguing with the cashier.
Worked example
Dina’s orthopedist orders an MRI. The imaging center is in-network on her Anthem PPO. The scheduler says “we’ll check benefits.” Two days later Anthem requires prior auth. The orthopedist’s staff submits records. Auth is approved for 30 days. Dina’s EOB later shows the MRI applied to her deductible (How to read medical bills and EOBs; Explanation of benefits).
If she had walked into a cash-pay imaging booth the same afternoon without auth, Anthem could deny the claim as “no prior authorization,” leaving her with a bill the plan never priced as a covered in-network service.
Timelines and your job as the patient
- Ask the clinic: “Does this need prior auth, and who submits it?”
- Ask for the auth reference number and expiration date.
- Confirm the facility and NPI match what was authorized.
- For drugs, ask whether a formulary alternative or step therapy applies first.
- Schedule inside the auth window; expired auth is a common denial reason.
- Keep portal screenshots from the Anthem, United, or member app.
Urgent and emergent care have different rules; life-threatening emergencies are not a reason to delay calling 911 while you chase paperwork.
If prior auth is denied
- Read the denial reason (not medically necessary, missing records, trial alternative first, out of network).
- Ask the clinician to submit an appeal or peer-to-peer review with clearer documentation.
- Check whether a covered alternative exists on the formulary or in-network.
- Use the plan’s internal appeal deadlines; external review may follow under state or federal rules.
- Broader claim-denial playbook: Denied insurance claims.
Do not assume a verbal “we’ll take care of it” from a scheduler equals an approved auth number.
Checklist
- Before non-urgent procedures or specialty drugs, ask about prior auth.
- Confirm who submits and how you will see the decision.
- Match facility, drug NDC/name, and dates to the approval.
- Save the auth number with your appointment reminder.
- If denied, start the appeal clock immediately with the clinician’s help—necessity language often drives the next letter (Medical necessity appeals).
- Separately budget deductible and coinsurance even after approval.
Educational only. Not medical or insurance advice. Plan documents and state rules control coverage.