The following links provide data elements descriptions for the Nationwide Ambulatory Surgery Sample (NASS).

Data element descriptions explain how the data element is coded in the HCUP databases, what the uniform values are, and State-specific coding practices. The descriptions are cumulative across all States and years of NASS data from 2016 to the current data year. Please note the following:

• Not all data elements in the NASS are uniformly coded across States. State-Specific notes are not available at this time.
• Not all data elements in the NASS are available from every State.

The NASS is a calendar year file. All NASS data elements are listed in alphabetical order below, along with the file location for each data element.

For a description of how HCUP data elements are coded, and uniform values, check the corresponding boxes below and then click the "View Description of Data Elements".