How does prior authorization work?

Prior authorization is your plan’s rule that it must approve some care before you get it, and in most plans a no is a decision you may appeal, first inside the plan and then to an independent reviewer (42 U.S.C. § 300gg-19; 45 CFR 147.136). In an emergency your plan may not require it at all, in network or out (the No Surprises Act, 42 U.S.C. § 300gg-111; 45 CFR 149.110(b)(1)).

How do I appeal a denied claim? — answered from the law, on provern.org