When the insurance company denies coverage, the dispute is between you and the insurer, not you and the provider. The right venue is the plan's internal appeal process, then external review, then federal court for ERISA-covered plans.
For any denial:
- Get the denial in writing, with the specific reason and the specific plan provision the insurer is relying on.
- Read your Summary Plan Description (SPD). This is the contract between you and the plan; it defines exactly what is and isn't covered. The SPD trumps the insurance company's general statements about coverage.
- Build an evidence-based appeal grounded in:
- The SPD's coverage language
- Your treating physician's medical-necessity determination
- Published clinical guidelines or peer-reviewed studies supporting the treatment
- Submit the appeal in writing within the plan's appeal window (typically 180 days for ERISA plans).
- If denied on internal appeal, request external review by an independent reviewer; this is required by federal law for most plans.
Insurance companies have legal teams that read appeals. Emotional appeals ("I'm a single parent, please help") don't move them and may signal you don't understand your contractual rights. What moves them is:
- Plan language that obligates them to cover the service
- Clinical evidence (your doctor, professional society guidelines, peer-reviewed studies) that the service is medically necessary
- Documentation that the denial reason doesn't match the facts
Treat the appeal like a contract dispute, because that's what it is.
The insurer is overriding your doctor's judgment. Counter with:
- Your treating physician's written statement explaining medical necessity for your specific case
- Specialty-society clinical practice guidelines supporting the service
- Peer-reviewed studies if the service is at the edge of standard practice
- Cite the SPD's language about respecting the treating physician's medical decision-making
The service exists but the insurer hasn't approved it for coverage. Counter with:
- FDA approval or clearance documentation
- Inclusion in major clinical practice guidelines
- Peer-reviewed efficacy studies
- Examples of other insurers covering the same service
This is a common reason for denying newer biomarker tests, advanced imaging, and certain genetic tests. The denial is often wrong on the facts.
- If it was an emergency: cite No Surprises Act (see [[04_no_surprises_act]]).
- If prior auth was attempted: provide the date you called and who you spoke to. Insurers' phone systems sometimes fail to log auth approvals.
- If the in-network alternative was not reasonably available: document the search you did.
This is the hardest to overturn because it's about plan design, not adjudication. But check:
- The SPD's actual language about the service category
- Whether the insurer has misclassified the service
- Whether parity laws apply (mental-health parity, especially)
Most employer-sponsored health plans in the US are governed by ERISA (the Employee Retirement Income Security Act of 1974). ERISA gives you specific rights:
- ERISA § 503: requires a "full and fair review" of denied claims, including specific timeframes for response.
- ERISA § 502(a): gives you the right to sue in federal court to recover plan benefits after exhausting internal appeals. Attorney's fees can be awarded to a prevailing claimant.
- The plan must produce, on request, the SPD, the actual plan document, and any internal guidelines or criteria used to evaluate your claim.
If your plan is ERISA-covered (most employer plans are; government and church plans are not), say so explicitly in your appeal letter. The phrase "I am preserving all rights under ERISA § 502(a)" is short, meaningful, and signals you know your remedies.
- Medicare and Medicaid, different appeal systems entirely
- TRICARE, federal
- Church plans and government employer plans, exempt unless they opted in
- Individual market plans (those purchased on the ACA exchange or directly), governed by ACA appeal rules and state law, not ERISA
- TennCare in Tennessee, Medicaid managed care, separate appeal process
For non-ERISA plans, the structure is similar but you don't have ERISA § 502(a) as your eventual hammer; you have state insurance department complaints and state-law remedies.
Marshall Allen credited Laurie Todd ("the Insurance Warrior") with much of his appeal-writing approach. Her published memos are pages long, dense with citations, and read more like legal briefs than letters. The pattern is reproducible:
- Open with one paragraph stating exactly what you want and why
- Devote the body to citing the SPD provisions that obligate the insurer
- Attach the clinical evidence as numbered exhibits
- Close with the specific relief requested and a deadline
templates/letter_insurance_appeal_erisa.md follows this pattern.
If internal appeal fails, request external review by an Independent Review Organization (IRO). The ACA requires this for most plans. The IRO is not paid by your insurance company; their decision is binding on the insurer. External review is free or low-cost (often a $25 filing fee that is refunded if you win) and overturns denials at a meaningful rate.
Whether ERISA or not, file a complaint with your state insurance department in parallel with the appeal. State regulators have leverage even over ERISA plans where state law applies. The complaint is free, takes 15 minutes, and creates pressure that often resolves the underlying dispute faster than the formal appeal process.
- [[04_no_surprises_act]], if the denial is for an out-of-network charge that the No Surprises Act prohibits
- [[06_small_claims]], note that small claims is for provider disputes; ERISA insurer disputes go to federal court instead