MA H4900

Requires health insurers, MassHealth, and the Group Insurance Commission to cover medically necessary acute treatment services, clinical stabilization services, and transitional support services for substance use disorder for up to 30 days without preauthorization

Defines "transitional support services" as short-term residential support following clinical stabilization to help adults and adolescents transition to outpatient or step-down addiction recovery care

Prohibits insurers from making utilization review decisions that restrict or deny services until a patient has received at least 30 consecutive days of treatment; carriers may begin utilization review on day 14 but cannot deny coverage before day 30

Requires facilities to notify carriers of admission and initial treatment plan within 48 hours, with medical necessity determined by the treating clinician in consultation with the patient

Mandates the Center for Health Information and Analysis to report on the effects of these coverage requirements by October 1, 2026 (initial report) and October 1, 2028 (final report), with the insurance provisions taking effect October 1, 2026