National Hospital Ambulatory Medical Care Survey Series

Investigator(s): National Center for Health Statistics

The National Hospital Ambulatory Medical Care Survey (NHAMCS) was inaugurated in 1992 to fill a gap in data about ambulatory medical care in the United States. Although the National Ambulatory Medical Care Survey (NAMCS) collects annual data on patient visits to physician offices, it excludes the hospital emergency room and outpatient department visits that make up a large part of the total ambulatory care received each year. The NHAMCS series provides data from samples of patient records selected from emergency departments and outpatient departments of a national sample of hospitals. Beginning with the 2009 data release, the NHAMCS will contain data from hospital-based ambulatory surgery centers; additionally, the NHAMCS will collect data from freestanding ambulatory surgery centers starting with the 2010 data release. These additions incorporate the design of the National Survey of Ambulatory Surgery (NSAS). The primary function of the NSAS, which was discontinued in 2006, was to collect data on surgical care in ambulatory surgery centers. The resulting national estimates describe the use of hospital ambulatory medical care services in the United States.