The South Carolina Budget and Control Board provides ambulatory surgery (AS) and emergency department (ED) records to HCUP in three separate files. One file contains information from ambulatory surgery centers associated with acute care hospitals. The second file contains ambulatory surgery data from freestanding surgery centers. The third file contains visits to hospital-based emergency departments, excluding records that have total charges less than $50.

The data include outpatient discharges from all South Carolina acute care hospitals derived from UB-92 records and discharges from South Carolina freestanding ambulatory surgery centers derived from HCFA 1500 records.

The following records were excluded from the HCUP South Carolina ambulatory surgery files:

• Discharges with disposition of "still a patient" were excluded in all years.
• In the 1998 database, 812 records (0.2% of the total records) were excluded because an accurate hospital identifier was not provided by the data source, and
• In the 1999 database, 3,019 records (0.7% of the total records) were excluded because an accurate hospital identifier was not provided.

Using the standard HCUP criteria for assigning records to the 2003 SASD and positive emergency room charges for assigning records to the SEDD, the source records are separated as follows:

• 30% of source records are assigned to the SASD
• 69% of source records are included in the SEDD
• 1% of source records are excluded.

Identifying Freestanding Facilities. Starting in 1998, the data element FREESTANDING identifies hospital-based and freestanding ambulatory surgery facilities. Prior to 1998, there are two identifiers on the SASD that allow a researcher to identify hospital-based and freestanding ambulatory surgery centers.

• DSHOSPID is the facility identifier provided by the data source.
• AHAID is the facility identifier used by the American Hospital Association.

1997 South Carolina SASD. Freestanding and hospital-based facilities are included in separate SASD files.