What is prior authorization, and what can a patient do if their insurer denies it?

Prior authorization (also called pre-authorization or pre-certification) requires healthcare providers to get approval from your insurer before delivering certain services, procedures, or medications. Insurers use it to verify medical necessity and control costs. If prior authorization is denied, you have the right to appeal through the insurer's internal process, and if that fails, to request an independent external review conducted by a third party unaffiliated with the insurer. Under the ACA, insurers must allow appeals and are bound by the decisions of independent external reviewers.