28 Tex. Admin. Code § 133.1
(a) This chapter applies to medical billing and processing for health care services provided to injured employees subject to a workers' compensation health care network established under Insurance Code Chapter 1305, and to injured employees not subject to such networks, with the following exceptions pertaining only to health care services provided to an injured employee subject to a workers' compensation health care network established under Chapter 1305:
Source Note:The provisions of this §133.1 adopted to be effective May 2, 2006, 31 TexReg 3544.