Medicare Part B, the Supplementary Medical Insurance (SMI) program, is a voluntary insurance program for the aged and disabled. The Part B program is supplemental to the Part A program and generally covers:
Part B covers “medical and other health care services” subject to specific coverage exclusions and conditions of coverage as well as exclusions resulting from the noninclusion of services in the statutory definition of the term “medical and other health care services.” 42 C.F.R. § 424.24.
Excerpt from Barry D. Alexander, Medicare Part B, Fundamentals of Health Law (American Health Lawyers Association Nov. 2011).
Federal funding for Part B services is derived solely from the Supplementary Medical Insurance (SMI) Trust Fund which is generated from general tax revenues and earned interest income. Beneficiaries contribute out-of-pocket for the care they receive under Part B in the form of monthly premium payments, deductibles and co-insurance.
Excerpt from Barry D. Alexander and James F. Flynn, Medicare Fundamentals : Intro, Fundamentals of Health Law (American Health Lawyers Association Nov. 2011).