What Is Medical Necessity
Medical necessity is the standard insurers use to determine whether a treatment, test, or procedure is appropriate and required to diagnose, treat, or manage your condition. Your insurer decides if a service meets this standard before approving payment. If they deny your claim, they typically cite medical necessity as the reason, claiming your doctor's recommendation doesn't meet their definition of what's necessary.
How Insurers Define It
Every insurance plan includes its own medical necessity criteria, usually buried in the plan documents or policy guidelines. These definitions vary significantly between insurers. One plan might approve an MRI for chronic back pain after 6 weeks of conservative treatment, while another requires 12 weeks before approving the same imaging. Some insurers use evidence-based guidelines from organizations like the American Medical Association, while others apply stricter internal criteria developed by their medical directors.
Insurers also evaluate medical necessity differently depending on whether services are routine, experimental, or cosmetic. A breast reconstruction after mastectomy is typically considered medically necessary under most plans and state laws. Bariatric surgery, however, often has strict requirements like a BMI of 40 or higher, documented weight loss attempts, or behavioral therapy participation before approval.
Where Medical Necessity Appears in Your Claims
- Pre-authorization decisions: When your doctor requests prior authorization, the insurer's medical reviewer evaluates whether the proposed treatment meets medical necessity. You'll see their determination in an approval or denial letter.
- EOB denials: Your Explanation of Benefits (EOB) statement shows claim denials with reason codes. Code 250 typically means "services not medically necessary." This is the insurer's way of saying your doctor's recommendation doesn't align with their criteria.
- Internal and external appeals: When you appeal a denial, you're arguing that the service IS medically necessary. You submit clinical evidence, physician statements, and medical literature to support why your condition requires the denied service.
State Insurance Regulations
Many states require insurers to use reasonable, clinically sound medical necessity standards. California and New York, for example, mandate that health plans apply medical necessity criteria consistently and make those criteria publicly available. Some states prohibit denials based solely on cost considerations or experimental status if adequate clinical evidence exists.
Under federal law (42 CFR 422.566), Medicare Advantage plans must cover services determined medically necessary by treating physicians unless the plan has an explicit coverage policy excluding the service. This gives Medicare beneficiaries stronger protections than commercial plan members.
Common Denial Patterns
- Insurer claims the condition isn't severe enough to warrant the treatment
- Less expensive alternatives exist, so the requested service isn't "necessary"
- Requested frequency or quantity exceeds plan guidelines (example: physical therapy sessions beyond plan limits)
- Service is deemed experimental or investigational despite clinical evidence supporting it
- Prior authorization wasn't obtained before service delivery
How to Challenge Medical Necessity Denials
- Request the insurer's criteria: Ask in writing for the specific medical necessity definition your plan used to deny the claim. They must provide this upon request.
- Submit physician documentation: Have your doctor write a letter explaining clinical reasoning for recommending the treatment, including relevant test results, diagnosis codes, and how the service addresses your specific condition.
- Provide clinical evidence: Include peer-reviewed studies, clinical guidelines from professional societies, and treatment protocols supporting the medical necessity of the denied service.
- File an adverse determination appeal: Most plans require internal appeals within 30 days of denial. If the insurer upholds the denial, request an external appeal to an independent reviewer within your state's timeframe, typically 4 to 5 business days.
Common Questions
If my doctor recommends a treatment, doesn't that make it medically necessary?
Not automatically. Your doctor's recommendation carries weight, but insurers have contractual rights to apply their own medical necessity criteria. However, if your doctor's recommendation aligns with clinical guidelines and your specific diagnosis, that strengthens your position considerably in an appeal. The key is documenting that the treatment is standard care for your condition.
Can an insurer deny a service because it's too expensive?
Not directly, though cost influences their decision-making indirectly. Insurers cannot deny a service solely because a cheaper alternative exists unless both are equally effective for your condition. They cannot deny based on price alone. However, if two treatments are clinically equivalent, the insurer can require you use the less expensive option first (called a step-therapy requirement), which must be specified in your plan documents.
What's the difference between a medical necessity denial and coverage exclusion?
A medical necessity denial means your plan covers the service in general, but the insurer believes your specific situation doesn't warrant it. A coverage exclusion means the plan simply doesn't cover that service for anyone. Coverage exclusions are much harder to appeal because the service isn't covered at all. Medical necessity denials are more winnable because the service is covered, you just need to prove you qualify.
Related Concepts
- Prior Authorization - the process where insurers evaluate medical necessity before approving treatment
- Adverse Determination - the formal denial decision you receive, often based on medical necessity criteria