What is major medical health insurance?

Major medical insurance is comprehensive coverage for hospitalization, surgery, emergency care, physician visits, prescription drugs, and preventive services. It typically includes an annual deductible, coinsurance or copays, and an out-of-pocket maximum. Employer-sponsored plans, ACA marketplace plans, and most private individual policies are major medical plans — unlike limited-benefit or supplemental-only products.

How do I appeal a denied claim on a major medical plan?

File a written internal appeal before your plan's deadline (often 180 days for ERISA employer plans, 60 days for ACA marketplace plans). Include your member ID, claim number, date of service, denial reason code from your EOB, and supporting clinical documentation. Request a written decision and, if denied again, request external review by an independent third party.

What is the difference between ERISA and ACA appeal rights?

ERISA governs most employer-sponsored self-funded and fully insured group plans. It requires written appeal procedures, access to your claim file under Section 503, and external review in most cases. ACA Section 2719 applies to non-grandfathered individual and small-group plans and sets specific timelines: urgent appeals within 72 hours, standard appeals within 30 days, and external review within 60 days of an internal denial.

Where do I find my major medical plan's coverage rules?

Request your Summary Plan Description (SPD) and Evidence of Coverage (EOC) from your employer's HR department or your insurer's member portal. For employer plans, the SPD explains benefits, exclusions, and appeal procedures. The EOC or Certificate of Coverage details medical necessity criteria, prior authorization requirements, and network rules that insurers cite in denials.

Does major medical insurance cover all medically necessary care?

No. Major medical plans cover services defined in your plan document, subject to medical necessity review, network status, prior authorization rules, and annual or lifetime limits where still permitted. A treatment can be clinically appropriate and still be denied if it is excluded, experimental per plan policy, or lacks required documentation.

How long does a major medical insurance appeal take?

Standard internal appeals typically must be decided within 30 days of receipt of complete documentation (72 hours for urgent or expedited appeals). External review adds 45 to 60 days after an internal denial. Medicare Advantage and Medicaid plans follow separate timelines — check your denial letter for the specific deadline and response window.

Can I request my insurer's claim file before appealing?

Yes. Under ERISA Section 503, participants in employer-sponsored plans have the right to review all documents, records, and other information relied upon in making an adverse benefit determination. Submit a written request to your plan administrator or insurer. The file often includes internal medical policy documents and nurse reviewer notes that help you target your appeal.

Can AppealFlow help me write a major medical insurance appeal letter?

Yes. AppealFlow.net offers a free appeal letter generator that drafts a formal, regulation-informed letter citing ERISA or ACA appeal rights, your specific denial reason, and supporting clinical evidence. You can customize the letter and export to PDF or Word — no account required.

Health Insurance Major Medical Plans: Coverage Rules and Your Appeal Rights

By Medical Claims Advocacy Team•13 min read•Updated August 2026

Major medical insurance covers hospitalization, surgery, emergency care, and physician services — but only within the rules defined in your plan document. When a claim is denied, you have the right to a formal internal appeal and, if needed, external review by an independent party under ERISA Section 503 or ACA Section 2719. Understanding your plan's coverage criteria is the first step to overturning a denial.

What Major Medical Insurance Actually Covers

Key Takeaway: Major medical plans are comprehensive policies with deductibles, coinsurance, and out-of-pocket maximums. They cover a defined set of services — not every treatment your doctor recommends. Denials usually mean your claim failed a plan rule, not that the care was unnecessary.

In my experience reviewing denied claims across employer, marketplace, and individual major medical plans, patients often assume “I have insurance, so it should be covered.” That is not how major medical works. Your insurer applies the specific benefit design in your Summary Plan Description (SPD) and Evidence of Coverage (EOC).

Major medical plans typically include:

Inpatient and outpatient hospital services — surgery, observation, emergency department
Physician and specialist visits — primary care, referrals, telehealth where covered
Diagnostic testing and imaging — lab work, X-ray, MRI, CT (often with prior authorization)
Prescription drug benefits — usually administered through a Pharmacy Benefit Manager (PBM)
Preventive care — ACA-required services at no cost-sharing for non-grandfathered plans

Common exclusions that trigger denials: cosmetic procedures, experimental treatments, services without prior authorization when required, out-of-network care without a network exception, and services exceeding frequency limits. Your EOB denial code tells you which rule your claim failed.

How Coverage Rules Lead to Claim Denials

Key Takeaway: Major medical denials fall into predictable categories: medical necessity, prior authorization, network status, coding errors, and benefit exclusions. The denial reason code on your EOB determines what evidence you need for an appeal.

The four denial types I see most often on major medical claims:

Medical necessity (CO-50): Insurer disagrees that the service meets their clinical criteria — common for imaging, surgery, and specialty drugs.
Prior authorization not obtained (CO-197): Your provider did not get pre-approval before the service was rendered.
Out-of-network (CO-96 or CO-109): Provider is not in your plan's network and no network exception was granted.
Benefit exclusion or plan limitation: Service is not a covered benefit under your specific plan design — weight-loss drugs, fertility treatment, or adult orthodontics are frequent examples.

Pull up your denial letter and EOB. Find the CARC/RARC remark codes and cross-reference them with your plan's medical policy on your insurer's website or by calling member services at the number on your insurance card.

Step-by-Step: How to Appeal a Major Medical Denial

Key Takeaway: File your written internal appeal before the deadline, attach a complete documentation packet, and request a written decision. Incomplete appeals are returned or denied on procedural grounds — costing you time you cannot recover.

Confirm your appeal deadline. ERISA employer plans: typically 180 days. ACA marketplace: 60 days. Medicare Advantage: 120 days for redetermination. Write the date on your calendar immediately.
Request your complete claim file. Under ERISA §503, you have the right to all documents the insurer relied on to deny your claim — including internal medical policies and reviewer notes.
Get a letter of medical necessity from your treating physician. It must address the specific denial reason code and cite accepted clinical guidelines where applicable.
Gather supporting records: visit notes, test results, prior authorization correspondence, and proof of failed conservative treatment if cited in the denial.
Write and submit your formal appeal letter. Include member ID, policy number, claim number, date of service, provider NPI, and a clear request for internal review.
Submit via the correct channel. Use Availity, your insurer's member portal, or the fax address on your denial letter. Confirm receipt and save confirmation numbers.
Follow up at 14 and 30 days. Standard appeals must be decided within 30 days (72 hours for urgent). Document every call with date, representative name, and reference number.
If denied again, request external review. An independent reviewer — not employed by your insurer — evaluates your case. This is often where well-documented appeals succeed.

Weak vs. Strong Appeal Language (Before & After)

Key Takeaway: Insurer medical directors approve appeals backed by plan-specific evidence and legal rights — not general complaints. Replace vague requests with denial codes, guideline citations, and documented clinical history.

❌ Weak Statement	✅ Strong Statement
“I have major medical insurance and my doctor ordered this test. Please cover it.”	“I request internal appeal for claim #CLM-2026-88421 (DOS 04/12/2026) denied under CO-50. Attached: letter of medical necessity citing ACR Appropriateness Criteria variant 7, PT records showing 8 weeks of failed conservative treatment, and MRI report confirming L4-L5 disc herniation (M51.26).”
“This denial is unfair. I pay premiums every month.”	“Under ERISA §503, I request review of the adverse benefit determination dated 05/01/2026. The denial cites plan medical policy MP-IMG-2024 Section 3.2. My physician's letter demonstrates all criteria in Section 3.2 are met, including documented radiculopathy and failed conservative management per plan requirements.”
“Can someone please look at my claim again?”	“I formally invoke my right to external review under ACA §2719 following internal appeal denial dated 06/15/2026. Member ID: ABC123456789, Policy: GRP-55001. Request independent review of medical necessity denial for outpatient knee arthroscopy (CPT 29881) with attached operative indication letter and orthopedic consultation notes.”

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Reading Your SPD and Evidence of Coverage

Key Takeaway: Your Summary Plan Description and Evidence of Coverage define what your major medical plan covers, what it excludes, and how appeals must be filed. Insurers deny claims based on these documents — your appeal must show your case meets the same criteria.

For employer-sponsored plans, request your SPD from HR or the plan administrator. For marketplace or individual plans, download your EOC from your insurer's member portal. Focus on these sections:

Schedule of benefits — deductibles, copays, coinsurance, and out-of-pocket maximums by service type
Exclusions and limitations — services not covered regardless of medical necessity
Prior authorization requirements — which services need pre-approval and the process
Appeal and grievance procedures — deadlines, required submission channels, and escalation to external review
Medical necessity definitions — how the plan defines medically necessary care

When your denial cites a specific medical policy section, quote that section in your appeal and demonstrate point by point how your clinical record satisfies each criterion. Generic appeals that ignore the cited policy language fail at high rates.

Submitting Appeals Through Insurer Portals (Availity, UnitedHealthcare, Aetna)

Key Takeaway: Most major medical appeals must be submitted through your insurer's designated portal or fax line. Submitting only by mail — or to the wrong department — is a common reason appeals get lost or denied for procedural reasons.

Platform	Used By	Appeal Submission
Availity	BCBS, Aetna, Humana, many regional plans	Member or provider portal → Claims → File Appeal; upload clinical packet
UnitedHealthcare	UHC commercial and employer plans	myUHC.com → Claims & Accounts → Appeal a Claim Decision
Aetna	Aetna CVS Health plans	Aetna.com member login → Claims → Dispute or Appeal
Cigna	Cigna commercial plans	myCigna.com → Claims → Appeal; fax backup to number on EOB

After submitting online, fax a copy of your complete appeal packet to the number on your denial letter as backup. Save portal screenshots and confirmation numbers. Follow up at 14 and 30 days if you have not received a written decision.

ERISA vs. ACA vs. Medicare: Appeal Rights Compared

Key Takeaway: Your appeal rights depend on which law governs your plan. ERISA employer plans, ACA marketplace plans, and Medicare each have different deadlines, review levels, and external review options.

Plan Type	Governing Law	Typical Appeal Deadline	External Review
Employer group (self-funded)	ERISA	180 days	Independent review organization (IRO)
ACA marketplace	ACA §2719	60 days (internal); 4 months (external)	State or federal external review
Medicare Advantage	42 CFR Part 422	120 days (redetermination)	ALJ hearing after reconsideration denial

Not sure which category your plan falls into? Check your insurance card and SPD. Employer plans with 50+ employees are usually ERISA-governed. Plans purchased on Healthcare.gov are ACA plans. Medicare Advantage cards show “Medicare” and your plan's MA contract number.

Realistic Timelines and Success Rates

Key Takeaway: Plan for 30–45 days for a standard internal appeal and 45–60 days for external review. Appeals with complete documentation and plan-specific arguments succeed roughly 40–55% on first submission — incomplete packets succeed less than 15%.

I want to be direct: an appeal letter alone does not override a clear plan exclusion. Major medical appeals succeed when your clinical record meets the insurer's own criteria — your letter frames that evidence and invokes your legal rights.

Expedited (urgent) appeal: 72 hours — use when delay poses serious health risk per your physician
Standard internal appeal: 30 days from receipt of complete documentation
External review: 45–60 days after internal denial

Common myth: Calling member services repeatedly without filing a written appeal does not start the appeal clock or create legal protections. You must submit a written appeal with supporting documentation to invoke ERISA or ACA review rights.

Five Mistakes That Kill Major Medical Appeals

Key Takeaway: The most common appeal failure is submitting a patient-written letter without addressing the specific denial code or citing the plan's own coverage criteria. Medical directors need targeted clinical evidence.

Ignoring the denial reason code. Your appeal must address the exact CARC/RARC code on your EOB — not a generic request for coverage.
Missing the deadline. No exceptions. Calendar the appeal date the day you receive the denial.
Not requesting your claim file. ERISA §503 gives you access to internal policies and reviewer notes that reveal exactly what the insurer looked for.
Submitting to the wrong channel. Prior auth appeals and post-service claim appeals follow different processes. Use the channel on your denial letter.
Stopping after internal denial. External review by an independent party is your strongest remaining option and is often underused.

Frequently Asked Questions

Answers to the most common major medical insurance and appeal rights questions from patients and providers.

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AppealFlow.net drafts a formal, legally grounded appeal letter citing ERISA or ACA rights, your denial code, and supporting clinical evidence — edit it live, then download as PDF or Word. No account required.

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Disclaimer: This article is for educational purposes only and does not constitute medical or legal advice. AppealFlow.net is not a healthcare provider or law firm. Success rates cited are estimates based on industry advocacy data and vary by plan. Always review appeal letters with your physician before submission. For medical emergencies, call 911. See our full disclaimer.