5 Costly Mistakes People Make When Appealing an Insurance Denial

You're going to appeal. But people make preventable mistakes that tank otherwise winnable cases. This guide shows you the 5 most common (and costly) mistakes, so you don't make them.

These aren't hard to avoid. But missing even one can mean the difference between approval and another rejection.

Mistake 1: Missing the Deadline

The most common and most irreversible mistake.

The problem: You have 180 days (USA), 12 months (UK), or another specific timeframe to appeal. Miss it, and you're done. The deadline is absolute.

Why people miss it:

• They're confused about when it starts ("Does it start from the denial letter or when I received it?")
• They're waiting for "the right time" to appeal
• They think they can appeal after the deadline if they have good reason
• Life gets busy and they forget

The cost: Permanent loss of appeal rights. No regulator can override a missed deadline. You'd have to go to court, which costs thousands.

How to avoid it:

1. Circle the deadline on your calendar the day you receive the denial
2. Count the days: [denial date] + [deadline period] = [appeal deadline]
3. Submit your appeal at least 5 days before the deadline (not the day of)
4. Confirm submission (email read receipt, registered mail confirmation)
5. If close to deadline, appeal first, send documentation second

Example: Denial dated January 1. 180-day deadline = July 1. Appeal by June 25 (giving yourself 6 days of buffer).

Don't wait. File now.

Mistake 2: Emotional Tone Instead of Professional Tone

Your appeal needs to persuade, not vent.

The problem: You're frustrated, in pain, stressed about medical bills. Your appeal letter sounds like it.

"Your company is cruel and greedy. How could you deny someone in my situation? I'm furious and demand immediate approval."

Why it fails:

• The insurer's reviewer is desensitized. Emotion doesn't move them.
• Angry tone makes you sound unreliable.
• It makes the reviewer defensive rather than open.
• It signals you might lose your temper in court if you escalate.

The cost: Same message, professional tone, gets approved. Same message, angry tone, gets denied.

How to avoid it:

• Write your appeal when you're calm
• Remove any phrase starting with "I feel," "You should," "This is wrong"
• Replace with facts: "According to [guideline], [fact]. The decision contradicts [evidence]."
• Have someone else read it before sending (they'll catch emotional language)
• Read it aloud—if you hear anger, rewrite

Before (emotional): "I cannot believe you denied this. My doctor says this treatment is necessary. You're putting profit before patients. This is unethical."

After (professional): "I respectfully disagree with the denial. My treating physician has provided a detailed clinical justification. According to NCCN guidelines, this treatment is recommended for my diagnosis. I request reconsideration."

The second version is more likely to be approved.

Mistake 3: Missing Evidence or Incomplete Documentation

You appeal with a vague story and no backup. The insurer reviews and denies again.

The problem: You say "my doctor thinks this is necessary" but don't provide the doctor's letter. You cite a guideline but don't attach it. You reference medical records but don't send them.

Why it fails:

• The reviewer doesn't have the information to reverse the decision
• Vague appeals sound weak
• The insurer assumes you don't have evidence (because you're not providing it)

The cost: Another denial, more delay, more stress.

How to avoid it:

1. Before you appeal, gather everything:

   • Doctor's letter explaining medical necessity
   • Clinical guidelines supporting your case
   • Complete medical records
   • Test results, imaging, specialist opinions
   • Policy language supporting coverage
   • Any communications about the condition

2. Organize it all in one package

3. Submit everything at once

4. Reference every document in your appeal letter: "I have attached: (1) Dr. Smith's letter dated January 5, (2) NCCN guidelines excerpt, (3) my complete medical records."

The reviewer needs evidence. Give them everything upfront.

Mistake 4: Accepting the First Rejection

Many people appeal once, get rejected, and give up.

The problem: They don't know they have a second appeal, or they don't know about external review, or they think they've exhausted options.

Why it fails:

• Many denials are overturned on second or third appeal
• External reviewers overturn internal decisions regularly
• Giving up leaves money on the table

The cost: Thousands in medical bills, plus stress from the medical condition being untreated.

How to avoid it:

1. Internal appeal rejected? Don't stop.
2. Escalate to external review (AFCA, FOS, OLHI, etc.)
3. External review rejects? Look into legal options
4. Track every "no" and escalate when available

Don't accept the first rejection as final. Most people don't know they have 2-3 levels of appeal available.

Mistake 5: Not Knowing Your Escalation Options

You've appealed. The insurer rejects. Now what? Many people don't know.

The problem: You don't know you can escalate to:

• Financial Ombudsman Service (UK)
• AFCA (Australia)
• OLHI (Canada)
• FIDReC (Singapore)
• State insurance commissioner (USA)
• Etc.

Why it fails:

• You stop appealing
• You might pay medical bills you don't owe
• You lose leverage because the insurer knows you won't escalate

The cost: Thousands in unnecessary bills, plus health consequences if treatment is delayed.

How to avoid it:

1. Look up your country's insurer regulator and ombudsman
2. Read their website before you appeal (so you know what's available)
3. In your internal appeal, reference external review: "If you don't approve, I will escalate to [external body]"
4. If rejected internally, immediately escalate

Know your options before you appeal. This changes how you negotiate.

Bonus Mistake 6: Waiting Too Long to Appeal

While you're waiting to gather perfect evidence, the deadline is ticking.

The problem: You want to assemble a perfect appeal package. So you wait. And wait. Meanwhile, the deadline approaches.

Day 170 of 180 days, you realize you're running out of time.

Why it fails:

• Rushed appeals are weaker
• You might miss documentation
• Stress increases
• If you miss the deadline, you lose everything

The cost: Your claim.

How to avoid it:

1. Appeal within 1 week of the denial
2. Gather evidence as you appeal, not before
3. Submit appeal first, send supporting docs within days
4. Perfect is enemy of done—submit and follow up

The insurer has time to review while you're gathering evidence. Don't delay.

Bonus Mistake 7: Not Requesting Peer-to-Peer Review

For medical necessity denials, peer-to-peer review often immediately flips the decision.

The problem: You write a letter. The insurer's medical reviewer reads it. They disagree.

But you never ask for a conversation between your doctor and the insurer's doctor.

Why it fails:

• Your doctor can explain clinical reasoning directly
• File-based review is more conservative than in-person discussion
• Many denials are based on miscommunication that a conversation fixes

The cost: Another rejection when approval was possible.

How to avoid it: In every medical necessity appeal, include:

"I request a peer-to-peer review between [your doctor's name] and your medical director. My physician is available [specific dates/times]. Phone: [number]. This conversation should address the clinical basis for the medical necessity determination."

Many appeals are approved immediately after this conversation happens.

Bonus Mistake 8: Admitting You Can Pay Out-of-Pocket

If you tell the insurer you'll pay for the treatment yourself, they have less incentive to approve.

The problem: You're frustrated and say, "Fine, I'll just pay for it myself."

The insurer thinks: "Great, we don't have to pay."

Why it fails:

• You've removed the insurer's financial incentive to approve
• You've signaled willingness to be out-of-pocket
• The appeal loses leverage

The cost: Money out of pocket that the insurer should have paid.

How to avoid it:

• Don't tell the insurer you'll pay yourself
• Don't tell the provider you'll cover costs
• Keep the pressure on the insurer: "I'm pursuing all appeal options to get approval"
• Only pay after all appeals are exhausted

Checklist: Avoiding These Mistakes

• I have noted my appeal deadline (date)
• I am appealing at least 5 days before the deadline
• My appeal letter is professional, fact-based (not emotional)
• I have gathered all evidence before appealing
• I am referencing every document in my appeal letter
• I understand my country's escalation options
• I know how many levels of appeal are available
• I am requesting peer-to-peer review (for medical denials)
• I have not told the insurer I'll pay myself
• I understand that first rejection is not final

Perfect is enemy of done. Appeal now, gather evidence concurrently, escalate when needed.

---

Disclaimer: ClaimBack provides AI-generated appeal assistance for informational purposes only. ClaimBack is not a law firm and does not provide legal advice. Always review your appeal letter before sending and consider professional advice for complex or high-value claims. Regulatory processes vary — always verify current procedures with your insurer or regulator.

---

Ready to fight your denial? ClaimBack analyses your case and writes a professional appeal letter in minutes — Start Free →