Tenn. Code Ann. § 56-7-2505: Phenylketonuria (PKU)

(a) Any individual, franchise, blanket or group health insurance policy, medical service plan, contract, hospital service corporation contract, hospital and medical service corporation contract, fraternal benefit society, or health maintenance organization that provides hospital expense and surgical expense insurance and that is delivered, issued for delivery, amended or renewed on or after July 1, 1995, shall provide coverage for the treatment of phenylketonuria.

(b) As used in this section, "treatment" means licensed professional medical services under the supervision of a physician and those special dietary formulas that are medically necessary for the therapeutic treatment of phenylketonuria.