Mass. Gen. Laws ch. 176O, § 16 – Clinical decisions regarding medical treatment made by treating physicians; payment for health care services ordered by treating physician or primary care provider

(a) The physician treating an insured, shall, consistent with generally accepted principles of professional medical practice and in consultation with the insured, make all clinical decisions regarding medical treatment to be provided to the insured, including the provision of durable medical equipment and hospital lengths of stay. Nothing in this section shall be construed as altering, affecting or modifying either the obligations of any third party or the terms and conditions of any agreement or contract between either the treating physician or the insured and any third party.
(b) A carrier shall be required to pay for health care services ordered by a treating physician or a primary care provider if:
1. (1) the services are a covered benefit under the insured's health benefit plan; and (2) the services are medically necessary. A carrier may develop guidelines to be used in applying the standard of medical necessity, as defined in this subsection. Any such medical necessity guidelines utilized by a carrier in making coverage determinations shall be:
(i) developed with input from practicing physicians and participating providers in the carrier's or utilization review organization's service area;
(ii) developed under the standards adopted by national accreditation organizations;
(iii) updated at least biennially or more often as new treatments, applications and technologies are adopted as generally accepted professional medical practice; and (iv) evidence-based, if practicable. In applying such guidelines, a carrier shall consider the individual health care needs of the insured. Any such medical necessity guidelines criteria shall be applied consistently by a carrier or a utilization review organization and made easily accessible and up-to-date on a carrier or utilization review organization's website to insureds, prospective insureds and health care providers consistent with subsection (a) of section 12. If a carrier or utilization review organization intends to implement a new medical necessity guideline or amend an existing requirement or restriction, the carrier or utilization review organization shall ensure that the new guideline or amended requirement or restriction shall not be implemented unless:
1. (i) the carrier's or utilization review organization's website has been updated to reflect the new or amended requirement or restriction; and (ii) the carrier or utilization review organization has assessed the limitation to show it is in compliance with state and federal parity requirements under chapter 26.
2. (c) With respect to an insured enrolled in a health benefit plan under which the carrier or utilization review organization only provides administrative services, the obligations of a carrier or utilization review organization created by this section and related to payment shall be limited to recommending to the third party payor that coverage should be authorized.