Reviewed September 2026.
A denied prior authorization means the plan refused coverage before (or without) approving the service or drug. That is different from a post-service claim denial on an EOB. What PA is: Prior authorization. Post-service claim path: Appeal a denied health insurance claim.
Name the denial reason first
| Denial reason (letter / portal) | First move |
|---|---|
| Not medically necessary / experimental | Clinician medical necessity letter + chart notes; request peer-to-peer |
| Missing clinical information | Office resubmits labs, imaging, prior therapies with the auth ID |
| Step therapy / try preferred drug first | Document failures or contraindications; drug cases may need a formulary exception |
| Out of network / wrong facility | Switch to an in-network site or appeal network determination with medical need |
| Auth expired / wrong CPT or NDC | Resubmit matching codes and dates; do not treat as a clinical fight |
| Administrative / eligibility | Fix member ID, effective date, or provider NPI with the plan |
Do not schedule elective care on a verbal “we’ll fix it” without an approval number.
Appeal steps (pre-service)
- Calendar the deadline on the denial (urgent vs standard clocks differ; many plans answer urgent PA appeals in 72 hours and standard in about 30 days, confirm your letter).
- Get the criteria the plan used (clinical policy ID or guideline name).
- Ask the ordering clinician for notes that map to that criteria. Peer-to-peer review (clinician-to-plan discussion) is optional and does not by itself file the formal appeal or stop the appeal clock, preserve the written appeal deadline either way.
- Submit via the portal or fax number on the letter; include member ID, auth reference, CPT/HCPCS or NDC, and attachments.
- Track the appeal reference number and expected decision date.
- If upheld, check external review rights for adverse benefit determinations (Marketplace and many employer plans). Broader denial playbook: Denied insurance claims.
Urgent and emergent care is not a reason to delay 911 while you chase paperwork. Life-threatening emergencies follow emergency rules, not elective PA.
Worked sketch: denied MRI prior auth
Maya’s orthopedist orders an MRI. UnitedHealthcare denies PA as “not medically necessary without 6 weeks of physical therapy.” Denial dated March 3; standard appeal window on the letter is 180 days to file, with a faster decision clock once filed.
| Day | Action |
|---|---|
| 1–2 | Download denial + clinical policy ID from the member portal |
| 1–5 | Orthopedist documents failed PT, positive exam findings, and prior imaging |
| 5 | Office files the formal internal appeal (new appeal reference #) and, if the plan allows the same week, also requests peer-to-peer; if peer-to-peer fails, the formal appeal clock is already running |
| Decision | Plan overturns; auth valid 30 days; Maya schedules inside that window |
If Maya had paid cash at an imaging booth the same week without auth, the later claim could still deny as “no prior authorization,” leaving a retail bill the plan never priced as covered in-network care.
Checklist
- Separate clinical denials from missing-info or coding denials.
- Put the auth reference number on every letter and portal note.
- Have the clinician map notes to the plan’s stated criteria.
- File before the printed deadline; keep screenshots.
- After approval, match facility, codes, and dates to the auth before the visit.
- Budget deductible and coinsurance even after PA approval.
Educational only. Not medical, legal, or insurance advice. Appeal rights and clocks depend on plan type (self-funded ERISA, fully insured, Marketplace) and state rules.