Health Insurance Denied? How to Appeal and Get External Review

That patient went through two internal appeals before an outside reviewer overturned the denial. Most people never get that far. In ACA Marketplace plans sold on HealthCare.gov, fewer than 1% of denied claims were appealed in 2023, according to KFF. Yet when people do push back, the result often changes. This guide covers how an appeal works, what to put in it, how external review works, and what your options are if the answer is still no.

How do you appeal a health insurance denial for a procedure?

File a written internal appeal with your insurer within 180 days of the denial notice, and include a letter from your doctor that answers the specific reason for the denial. That deadline comes from HealthCare.gov, which also sets how long the insurer has to decide: 30 days if the service has not happened yet, 60 days if you have already had it, and 72 hours for urgent care.

You can use the insurer's own appeal paperwork or simply write a letter with your name, claim number and member ID. Your state's Consumer Assistance Program can file the appeal for you. Many employer plans that are self-funded follow federal Department of Labor rules instead of state rules, so check which kind of plan you have before you count the days.

Can insurance deny surgery your doctor says is medically necessary?

Yes. Your doctor recommends the treatment, but the insurer decides whether it meets the plan's own coverage criteria, and those two things do not always match. That is why the most useful thing you can do is find out exactly why the claim was denied.

The denial letter should give a reason. If it only says "not medically necessary", ask the insurer in writing for the clinical criteria it used, the plan section it relied on, and the records it reviewed. In KFF's 2023 review of Marketplace plans, insurers gave "other" as the reason for 34% of in-network denials, administrative reasons for 21%, excluded services for 14%, missing prior authorization or referral for 9%, and medical necessity for only 6%. An administrative or paperwork denial is often the easiest kind to fix.

Your doctor can also ask for a peer-to-peer call with the insurer's medical reviewer. It does not always work, and some doctors choose a different covered test instead.

How does an external review work?

If the insurer upholds its denial, you can ask an independent reviewer outside the company to look at the case, and the insurer must accept that decision. According to HealthCare.gov, you have 4 months after the final denial to ask. A standard review must be decided within 45 days and an expedited one within 72 hours. Where HHS runs the process there is no charge, and elsewhere the fee cannot be more than USD 25.

In urgent cases you can file the internal appeal and the external review at the same time. External review is used rarely: Marketplace enrollees filed about 5,000 external appeals in 2023, according to KFF. In Medicare Advantage, where the process is different, KFF found that 80.7% of appealed prior authorization denials were partly or fully overturned in 2024, although only 11.5% of denials were appealed.

How do you dispute a hospital bill after insurance denies part of it?

Start by asking the hospital for an itemized bill and comparing it with your insurer's explanation of benefits line by line. Many disputed bills come from a wrong billing code, a duplicate charge, or a claim sent to the wrong address, and those are fixed by the billing office resubmitting the claim, not by an appeal.

If a service was billed as out of network but you had no choice of provider, such as an anesthesiologist at an in-network hospital or care in an emergency, the federal No Surprises Act may protect you. Ask the hospital to hold the bill while the claim is reprocessed or appealed, and write down every call with the date and the name of the person you spoke to. If you get nowhere, the regulator is your state insurance department for most plans, or the Department of Labor for self-funded employer plans.

What can you do if the appeal fails or takes too long?

You still have choices. You can ask the hospital or surgery center for its self-pay price, apply for its financial assistance program, or ask your doctor whether a covered alternative would do the same job. For legal questions, such as whether to sue, talk to a lawyer or your state's Consumer Assistance Program.

Some people also price the same treatment abroad. In China, a foreign patient pays the hospital's listed price directly, with no insurer approval step. Patients in China report paying a median of CNY 484 (≈ USD 72) for a plain MRI of one body part, about CNY 1,500 (≈ USD 220) for a sedated colonoscopy and gastroscopy without polyp removal, and a median of CNY 34,650 (≈ USD 5,150) for a hip replacement before insurance (Chinese patient reports, 2025–26). Foreign patients pay these full prices, and international departments charge more. Flights, hotel and time away from work add to the total, so it is not always the cheaper path.

If you go this way, keep your home appeal running in parallel. Original Medicare usually does not cover planned care outside the US, according to Medicare.gov, and private plans vary. As of October 2026, no plan is required to pay for treatment you choose to have abroad, so ask your insurer for written confirmation before you book, and check visa rules with the Chinese embassy.