Learn The Lingo

Learn the Lingo: Key Terms for Navigating the Value Based Care World

With the shift toward value-based payment models, pharmacists are seizing new opportunities to improve patient care in medical homes, accountable care organizations, and other innovative care models. This resource includes acronyms and terminology commonly used when practicing in or discussing innovative practice models. Each term includes a short description and references so you can further your practice in a value based care world. This is the first of multiple volumes that will be published by the Medical Home/ACO SIG.

Shruthi Gowda
/ Categories: Learn the Lingo

Medicare Administrative Contractor (MAC)

Medicare Administrative Contractor (MAC)

Definition: A Medicare Administrative Contractor (MAC) is a private health care insurer responsible for managing policies and processing Medicare Part A, Medicare Part B, and durable medical equipment (DME) claims for Medicare Fee-For-Service (FFS) beneficiaries.1

The concept of MACs originated from section 911 in the Medicare Prescription Drug Improvement and Modernization Act of 2003, which called for replacing Part A fiscal intermediaries and Part B carriers with MACs.2

Through the Center for Medicare and Medicaid Services (CMS), MACs are awarded contracts regionally, with jurisdictions often encompassing several states. In the United States, there are 12 regional MACs assigned to manage Medicare Part A and B claims, 4 of which have additional jurisdictions for processing home health and hospice claims.

Health care providers enrolled in a Medicare FFS program rely on a MAC to serve as the primary operational contact for activities including provider inquiries, processing Medicare FFS claims, enrolling providers in the FFS program, and establishing local coverage determinations (LCDs). Durable medical equipment, orthotics, and prosthetics (DMEPOS) claims are processed through a separate MAC, with 4 jurisdictions assigned in the United States.

How it relates to ACO/PCMH: MACs assist providers, including pharmacists, who are working under ACOs/PCMHs to answer questions related to claims and billing for services provided to Medicare FFS beneficiaries. Any claims submitted by an ACO/PCMH are processed through the designated MAC in that region.

Not all ACOs are contracted with a pharmacy or have a formal relationship with one. However, ACOs contracting pharmacies have a broader range of services and greater experience with payment reform.3 Pharmacies contracted with a MAC can be reimbursed for covered Medicare Part B services such as immunizations, tests, and diabetes self-management training (DSMT).

Involved organizations/oversight: CMS procures and manages MAC contracts under the requirements of the Federal Acquisition Regulation (FAR) and HHS Acquisition Regulation (HHSAR). In addition, each MAC is required to have its own compliance program.


  1. CMS. Medicare administrative contractors. Baltimore: CMS. Available at: Accessed March 10, 2023.
  2. H.R. 1–Medicare Prescription Drug, Improvement, and Modernization Act of 2003. Washington, DC: U.S. Congress. Available at: Accessed March 10, 2023.
  3. Colla CH, Lewis VA, Beaulieu-Jones BR, et al. Role of pharmacy services in accountable care organizations. J Manag Care Spec Pharm. 2015;21(4):338–44.

Contributing authors

Sara Touchan, PharmD

PGY-1 Pharmacy Practice Resident

Wentworth-Douglass Hospital

Dover, NH


Amber Mercuro, PharmD, BCACP

Clinical Ambulatory Pharmacist

Wentworth-Douglass Hospital

Dover, NH

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