A real scenario (details changed)
Sarah Chen, 34, had been dealing with lower back pain for three months. Her orthopedist ordered an MRI of the lumbar spine. UnitedHealthcare denied the prior authorization request with the reason: “Not medically necessary — conservative treatment not adequately documented.”
Sarah had actually completed six weeks of physical therapy and tried two rounds of prescription NSAIDs. That information just wasn't in the original PA request. Her appeal — which included documentation of both — was approved within eight days.
That gap — information that exists but wasn't submitted — is behind most avoidable denials. Understanding why your insurer said no is the first step to fixing it.
What prior authorization actually means
Prior authorization (PA) is your insurance company's way of approving certain procedures, medications, or services before you receive them. Without it, the insurer can refuse to pay — even if the treatment is medically appropriate and your doctor ordered it.
The process exists to control costs and ensure treatments meet clinical criteria. In practice, it creates a significant administrative burden for patients and providers alike, and denial rates have been rising. But the right to appeal a denial is federal law — insurers are required to provide a written explanation of any denial and a clear appeals process.
What your denial letter is actually saying
Denial letters are written in insurance language that often obscures the actual reason. Here's what the most common denial reasons mean in plain English — and critically, what each one tells you about what your appeal needs to include.
Most common PA denial reasons (commercial insurance)
🔴 “Not medically necessary”
What it means: The insurer's clinical reviewer concluded that the treatment doesn't meet their criteria for medical necessity — usually because the documentation in the request didn't establish that conservative alternatives were tried first, or didn't demonstrate sufficient severity.
What your appeal needs: Documentation of everything you've already tried (physical therapy, medication trials, previous imaging), objective measures of severity (pain scores, functional limitations, specialist notes), and — if your doctor can provide it — a letter of medical necessity that directly addresses the insurer's criteria.
🟡 “Step therapy requirements not met” / “Fail first”
What it means: Your insurer requires patients to try cheaper treatments first before approving a more expensive one. The original request didn't show that you completed the required “steps.”
What your appeal needs: Records showing every prior treatment — what was tried, when, at what dose, for how long, and why it didn't work or had to be stopped. Many insurers also have a step therapy exception process if you have a medical reason the required drug is inappropriate for you.
🟣 “Missing clinical documentation”
What it means: The request was incomplete — specific records, test results, or forms that the insurer requires weren't included.
What your appeal needs: This is actually the most straightforward denial to overturn — just supply the missing items. The appeal overturn rate for missing documentation is among the highest at roughly 76%.
🔵 “Non-covered service”
What it means: The insurer is claiming this treatment isn't covered under your plan.
What your appeal needs: Review your plan's Summary of Benefits and Coverage (SBC). If you believe the service is covered, cite the specific coverage provision in your appeal. If it genuinely isn't covered, an appeal is unlikely to succeed — but you may have options through your state's insurance commissioner or an external review.
How to file your appeal, step by step
Step 1: Record the denial and gather what you need
Before you write a word, make sure you have:
- Your denial letter (the exact denial reason is critical — it dictates everything in the appeal)
- Your insurance member ID card and group number
- The authorization number from the original request (usually on the denial letter)
- The CPT or procedure code that was denied
- Your doctor's name, NPI number, and practice fax number if you have them
Note your appeal deadline. Federal law requires insurers to tell you the deadline in the denial letter. For commercial plans it's typically 60–180 days from the denial date. Miss it and you lose the right to an internal appeal.
Step 2: Let AI draft the appeal letter
The hardest part of an appeal for most patients is translating medical and insurance jargon into a professional letter that directly addresses the insurer's stated reason. FaxSeal's AI does this automatically.
When your original PA comes back denied, open the tracking page. You'll see a denial panel showing the reason that was recorded. Click “Generate appeal letter” — the AI reads the denial reason and writes a complete appeal letter targeting it specifically.
For Sarah's UnitedHealthcare denial (“conservative treatment not adequately documented”), the generated letter would:
What the AI-generated appeal letter includes
- ✓ Opens by stating the denial reason and asserting it is incorrect based on the medical record
- ✓ Documents the 6-week physical therapy course with start/end dates and provider
- ✓ Documents the two NSAID trials with drug names, doses, duration, and reason discontinued
- ✓ Cites UnitedHealthcare's own clinical policy for lumbar MRI authorization criteria
- ✓ Notes that the criteria for conservative treatment failure have been met
- ✓ Requests expedited review if clinically appropriate
- ✓ Lists attachments to include (PT records, pharmacy records)
You review and edit the letter — add anything specific to your situation, include your doctor's contact information, or attach additional supporting documents. Then submit it directly from the same page.
Step 3: Check what documentation gaps the AI flagged
When you open the appeal form, FaxSeal automatically runs a documentation check using your denial reason as the lens. It scans what's already in your notes and flags anything that's still missing — before you submit.
For a “not medically necessary” denial, it might flag:
No pain scale documented — include a current functional pain score (VAS or numeric scale) to demonstrate severity objectively.
Physical therapy records not referenced in the letter body — mention the PT course explicitly even if you're attaching the records separately.
These warnings are specific to your denial reason — not generic suggestions. Addressing them before you submit is what turns a weak appeal into a strong one.
Alongside the documentation check, FaxSeal also shows an approval probability estimate — a percentage score with a one-sentence explanation of what's driving it. For example:
74%
Likely approved
Step therapy is well-documented and the denial reason is directly addressed. Adding objective functional scores would strengthen further.
The score factors in your insurer's known denial patterns and how well your appeal letter addresses them. A low score before you submit is a signal to strengthen the letter — not a prediction that you'll lose. It's the same check a benefits coordinator would run before submitting on your behalf.
Step 4: Ask the PA Assistant what else to include
The PA Assistant at /dashboard/prior-auth/assistant can answer specific questions about your insurer's appeal process, what they typically require, and how to strengthen your case.
UHC denied my MRI for lower back pain saying conservative treatment wasn't documented. How long do I have to appeal and what should I send?
For UnitedHealthcare commercial plans, you typically have 60 days from the denial date to file an internal appeal. Check your denial letter — it must state the deadline by law.
For a lumbar MRI denied as “not medically necessary,” UHC's clinical criteria require documentation of: (1) acute onset or trauma, OR (2) 6+ weeks of symptoms that haven't resolved with conservative care including physical therapy or chiropractic. Since you've done PT, attach those records directly — the dates and duration matter more than the therapist's notes.
If the denial isn't overturned internally, you have the right to an Independent Medical Review (IMR) — a state-mandated external review where an independent physician who has no connection to UHC reviews your case. IMR overturn rates for diagnostic imaging denials are higher than most people expect.
What to add to your appeal that wasn't in the original
Insurers deny on grounds they have to articulate. Use that denial reason as your target. The most effective additions depend on why you were denied:
| Denial reason | Highest-impact additions |
|---|---|
| Not medically necessary | PT records, medication trial documentation, functional limitation statement from your doctor, pain scale scores |
| Step therapy | Pharmacy records of prior drugs, chart notes documenting side effects or lack of response, step therapy exception letter if applicable |
| Missing documentation | Whatever the denial letter says was missing — request the complete list from your insurer if it isn't clear |
| Any | Clinical guidelines from a medical society (ACR, ACS, AHA) that support your treatment — insurers can't easily dismiss published standards of care |
Your odds: appeal overturn rates by denial reason
Not all denials are equally likely to be overturned. Missing documentation is the most recoverable — the insurer said no because they didn't have what they needed, and supplying it in the appeal often resolves the issue immediately. Step therapy and “not medically necessary” denials require more work but are still frequently overturned.
PA appeal overturn rates by denial reason
Composite from AHIP appeal data and state insurance commissioner annual reports. Rates vary by state, plan type, and insurer.
What the timeline looks like
Filing the appeal itself takes less than 20 minutes if you use AI to draft the letter. The wait for the insurer's decision is the slow part — 30 to 60 days for a standard internal appeal. Urgent appeals (where a delay would seriously harm your health) must be decided within 72 hours by federal law.
Appeal process timeline
Time for patient steps is with AI assistance. Insurer decision time: 30–60 days standard, 72 hours urgent (federal mandate for urgent appeals).
If the internal appeal fails: external review
Under the ACA, if your internal appeal is denied, you have the right to an Independent Medical Review (IMR) — an external review by physicians who have no connection to your insurer. External reviewers overturn internal decisions at rates that vary by state and procedure type, but the process exists precisely because internal appeals are reviewed by the same insurer that denied you.
Request external review immediately after an internal denial — deadlines are typically 60 days. Your insurer must provide the external review process information with every internal denial notice.
How much does it cost to file an appeal?
FaxSeal charges a small flat fee per submission — there is no subscription and no account required to pay by card. Credits can be bought in bundles if you plan to submit multiple requests, and they never expire.
| How you submit | Pay by card | Pay with credits |
|---|---|---|
| Fax directly to insurer | $4 | 2 credit ($12.99 buys 10) |
| Download PDF — portal, phone, or mail | $2.99 | 2 credit |
| AI appeal letter + documentation check + approval estimate | Included | Included |
The exact cost is shown on the submission form before anything is charged. Credits never expire — if you buy a Starter Pack ($12.99 for 10 credits) and only use one, the rest stay in your account. See all options →
File your appeal with AI assistance
FaxSeal's patient mode guides you through the PA appeal process — no clinical expertise needed. AI drafts the appeal letter targeting your specific denial reason, and you can submit by fax, portal, phone, or mail.
Start your appeal →Questions about your insurer's process? Ask the PA Assistant