Ambulatory care is outpatient healthcare that is provided in a range of facilities where patients do not remain overnight.
Some examples of settings that provide ambulatory care include hospital-based outpatient clinics, non-hospital based clinics and physician offices, urgent care centers, ambulatory surgical centers, public health clinics, imaging centers, oncology clinics, ambulatory behavioral health and substance abuse clinics, and physical therapy and rehabilitation centers. Centers for Disease Control and Prevention, Guide to Infection Prevention in Outpatient Settings: Minimum Expectations for Safe Care.
Section 4523 of the Balanced Budget Act of 1997 (BBA), as amended by sections 201 & 202 of the Balanced Budget Refinement Act of 1999 (BBRA), provides authority for CMS to implement a prospective payment system under Medicare for:
(1) hospital outpatient services (OPPS),
(2) certain Part B services furnished to hospital inpatients who have no Part A coverage, and
(3) partial hospitalization services furnished by community mental health centers.
Services paid under the OPPS are classified into groups called Ambulatory Payment Classifications or APCs. A payment rate is established for each APC. Services in each APC are intended to be similar both clinically and in resource utilization. Depending on the services provided, hospitals may be paid more than one APC for an encounter or visit.
CMS's first final rule for OPPS was published in the Federal Register on April 7, 2000 (65 FR 18434). OPPS went into effect for services with dates on service on and after August 1, 2000.
Excerpt from Valerie Rinkle, The 2012 Outpatient Prospective Payment System (OPPS) Update, Institute on Medicare and Medicaid Payment Issues (American Health Lawyers Association 2012).