How do I appeal an insurance denial?

A denial letter is the start of a process, not the end. HealthCare.gov lays out your rights: the insurer must tell you why it denied the claim and how to dispute it, and you have the right to two levels of appeal. Level one, the internal appeal: you ask the insurer to conduct a full and fair review of its own decision - and if the case is urgent, it must speed up the process. Level two, the external review: an independent third party, not the insurer, reviews the decision - and if they overturn it, the insurer must pay. The practical playbook: read the denial letter for the exact reason code (missing prior authorization, 'not medically necessary,' out-of-network, coding error - coding errors are common and the easiest wins); gather the evidence (your doctor's letter of medical necessity is the single strongest document - ask for one explicitly); file before the deadline in the letter (typically 180 days for internal appeals); send it trackable and keep copies of everything; and get help free - your state's insurance department takes complaints and many states have consumer assistance programs that fight with you. Denials are overturned often enough that appealing is always worth the paperwork. Pymander is a free AI doctor, 24/7 by text, that can help you decode the denial letter.