Your insurance denied coverage for a needed procedure — what to do next

A denial letter from a health insurer is designed to end the conversation. Dense, technical, written in a tone that suggests the decision is final. It is not. The majority of denied claims that reach internal review are overturned, and the number rises further at external review.

The difference between a denial that stands and one that gets reversed is almost always procedure, not medicine. Here is how to work the process.

Read the denial letter like a lawyer, not a patient

The first move is to find and underline four specific pieces of information. Every denial letter contains them, though they may be buried in different sections.

1. The stated reason for denial. "Not medically necessary." "Experimental or investigational." "Not a covered service." "Out of network." "Prior authorization not obtained." "Failure to meet plan requirements." Each of these has a different appeal strategy.
2. The specific plan provision or policy cited. Insurers are required to tell you which policy language they used. This is the ground on which the fight happens.
3. The deadline to appeal. Internal appeals are typically 180 days from the denial, but plans vary. External reviews are usually 4 months from final internal denial. Miss the deadline and you lose the right to appeal.
4. The appeal process the plan requires. Some plans have multiple levels of internal review. Knowing the required sequence is essential.

The letter will also include information about your right to request the plan's clinical review criteria and any medical records relied on. Request both. You have a legal right to them.

The four most common denials and what actually works

"Not medically necessary"

The most common denial and the most appealable. The insurer's position is that the procedure isn't justified by the medical facts. Your position is that it is — supported by your physician's judgment and the standard of care for your condition.

What wins this appeal:

• A detailed letter from the treating physician explaining medical necessity in the specific clinical language the plan's criteria use
• Clinical guidelines from medical societies supporting the treatment (the AMA, specialty boards, or peer-reviewed sources)
• Prior treatments attempted and why they failed
• Evidence that the denial decision was made without review by a physician in the relevant specialty

A generic "this is necessary" letter rarely wins. A specific letter that engages with the plan's stated criteria wins often.

"Experimental or investigational"

This denial claims the treatment hasn't met the plan's threshold for established care. It's increasingly common for newer therapies — targeted cancer treatments, certain surgeries, specialized mental health care.

What wins this appeal:

• FDA approval status, if applicable
• Peer-reviewed studies supporting the treatment's efficacy
• Coverage of the same treatment by other major insurers (Medicare coverage, in particular, is influential)
• Clinical practice guidelines that include the treatment as standard care

"Out of network"

The plan says the provider isn't in the network and so the claim is denied or paid at a reduced rate. Two sub-appeals work here depending on facts.

Emergency situations. Federal law (the No Surprises Act) protects patients from surprise out-of-network bills for emergency care and for certain services at in-network facilities. If either applies, the insurer is generally required to cover at in-network rates.

Network adequacy. If no in-network provider in your area offers the care you need — a specialist, a specific surgery, or a provider with appropriate wait times — the plan may be required to cover out-of-network at the in-network rate. This is a network adequacy challenge and it often works.

"Prior authorization not obtained"

The provider didn't get approval from the insurer before the service. This denial usually lands on the patient even though the failure was the provider's.

What wins this appeal:

• Documentation of the provider's attempts to get authorization
• Evidence the service would have been approved if requested
• Retroactive authorization requests where allowed
• In some cases, direct negotiation between the provider and the insurer to take the charge off the patient

The internal appeal — the first round

Every appeal starts with the plan's internal review. You submit a written appeal that includes:

• A cover letter stating the claim number, the denied service, and your specific grounds for appeal
• A clinical letter from your physician
• Supporting medical records
• Supporting research or guidelines
• Any patient-specific information the plan might have missed

Submit by certified mail or the plan's secure portal. Keep copies of everything. The plan has a defined window to respond — typically 30 days for pre-service denials, 60 days for post-service.

If the internal appeal fails, you usually have a second level of internal review. Take it. Each level gives the plan another chance to reverse and also builds the record for external review.

External review — the second round

Once internal review is exhausted, most plans (under the Affordable Care Act) are subject to independent external review by a third party not affiliated with the insurer. External review is binding on the insurer.

External reviewers are independent physicians in the relevant specialty. They review the record, apply the plan's criteria, and make a decision — often faster than internal review (within 45 days, or 72 hours for urgent cases).

Approval rates at external review are meaningfully higher than at internal review, which is a reminder that internal review is often the insurer's first attempt to defend its own position rather than an independent assessment.

What if it's still denied?

If external review upholds the denial, remaining options include:

• State insurance department complaint (Virginia's State Corporation Commission Bureau of Insurance handles these)
• ERISA litigation in federal court (for employer-sponsored plans)
• State-court litigation (for individually purchased plans)

These steps require attorney involvement and a realistic cost-benefit analysis. They are not always worth pursuing, but for significant denied claims — major surgery, life-altering treatment, sustained care — they often are.

Mistakes that sink otherwise-winnable appeals

• Missing the appeal deadline
• Submitting a short or emotional appeal letter without supporting documentation
• Relying only on the physician's recommendation without engaging the plan's specific criteria
• Failing to request the plan's internal clinical criteria
• Not appealing because the denial "felt" final

Most denied claims that should have been approved remain denied because the patient gave up. The system counts on that.

This article provides general information and is not legal or medical advice. Appeal rules vary by plan type (ERISA, individual, Medicare, Medicaid) and by state. Please consult an attorney to review your specific denial.