Texas Health and Safety Code - HEALTH & SAFETY § 166.040. Patient Certification and Prerequisites for Complying with Directive

(a) An attending physician who has been notified of the existence of a directive shall provide for the declarant's certification as a qualified patient on diagnosis of a terminal or irreversible condition.

(b) Before withholding or withdrawing life-sustaining treatment from a qualified patient under this subchapter, the attending physician must determine that the steps proposed to be taken are in accord with this subchapter and the patient's existing desires.