A Practice Note addressing the internal claims and appeals rules under the Affordable Care Act (ACA), which expanded the substantive and procedural claims requirements for non-grandfathered group health plans and health insurers. The ACA's required changes affected the scope of adverse benefit determinations, notice for urgent claims, full and fair review rights for claimants, content and non-English language distribution rules for notices, conflicts of interest, and continued coverage during appeals. The rules also include a strict compliance requirement, subject to limited exceptions.