This subchapter applies only to:
(1) a health benefit plan offered by a health maintenance organization operating under Chapter 843, except that this subchapter does not apply to:
(A) the child health plan program under Chapter 62, Health and Safety Code, or the health benefits plan for children under Chapter 63, Health and Safety Code; or
(B) the state Medicaid program, including the Medicaid managed care program operated under Chapter 540 or 540A, Government Code, as applicable;
(2) a preferred provider benefit plan or exclusive provider benefit plan offered by an insurer under Chapter 1301; and
(3) a person who contracts with a health maintenance organization or insurer to issue preauthorization determinations or perform the functions described in this subchapter for a health benefit plan to which this subchapter applies.