Tex. Civil Practice and Remedies Code § 146.002

(a) Except as provided by Subsection (b) or (c) and subject to Subsection (c-1), a health care service provider shall bill a patient or other responsible person for services provided to the patient not later than the first day of the 11th month after the date the services are provided.

(b) If the health care service provider is required or authorized to directly bill the issuer of a health benefit plan for services provided to a patient, the health care service provider shall bill the issuer of the plan not later than:

(1) the date required under any contract between the health care service provider and the issuer of the health benefit plan; or

(2) if there is no contract between the health care service provider and the issuer of the health benefit plan, the first day of the 11th month after the date the services are provided.

(c) If the health care service provider is required or authorized to directly bill a third party payor operating under federal or state law, including Medicare and the state Medicaid program, the health care service provider shall bill the third party payor not later than:

(1) the date required under any contract between the health care service provider and the third party payor or the date required by federal regulation or state rule, as applicable; or

(2) if there is no contract between the health care service provider and the third party payor and there is no applicable federal regulation or state rule, the first day of the 11th month after the date the services are provided.

(c-1) If a health care service provider provides services to a patient that are related to a personal injury claim for which the patient is represented by an attorney and unless otherwise directed by the patient or other responsible person, the provider may satisfy the requirements of Subsection (a) by submitting the bill to the patient's attorney not later than the first day of the 11th month after the date the services are provided.

(d) For purposes of this section, the date of billing is the date on which the health care service provider's bill is:

(1) mailed to the patient, responsible person, or attorney representing the patient, as applicable, postage prepaid, at the address of the patient, responsible person, or attorney representing the patient as shown on the health care service provider's records; or

(2) mailed or otherwise submitted to the issuer of the health benefit plan or third party payor as required by the health benefit plan or third party payor.