How do I appeal a health insurance claim that was denied as 'not medically necessary'?

You have a legal right to appeal under the ACA. First request the denial reason and your policy's medical-necessity criteria in writing. File an internal appeal with a letter from your doctor explaining why the treatment is necessary, attaching clinical notes and any supporting guidelines. Meet the deadline stated in the denial, often 180 days.

If the internal appeal is upheld, you're entitled to an external review by an independent third party whose decision the insurer must follow. For urgent situations you can request an expedited appeal that's decided quickly. Keep a detailed record of every call, name, and reference number. Your state insurance regulator and the federal Consumer Assistance Program can help you navigate the process.