Skip Navigation

NASS Description of Data Elements
The Nationwide Ambulatory Surgery Sample (NASS) is a set of ambulatory surgery databases included in the HCUP family. These databases are created by AHRQ through a Federal-State-Industry partnership.
 
NASS Description of Data Elements

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".
Check the corresponding boxes and then click
HCUP Data Element Descriptive Title Years File(s)
Select All Data elements change frequently, and are only current as of the date generated.
AGE Age in years at admission 2016 Encounter
AMONTH Admission month 2016 Encounter
AWEEKEND Admission day is on a weekend 2016 Encounter
CPTn CPT-4/HCPCS procedures 2016 Encounter, Supplemental
CPTCCSn Clinical Classifications Software (CCS): services and procedures classification 2016 Encounter, Supplemental
DISCWT Weight to discharges in the universe 2016 Encounter, Hospital
DISPUNIFORM Disposition of patient, uniform coding 2016 Encounter
DQTR Discharge quarter 2016 Encounter
FEMALE Indicator of sex 2016 Encounter
HOSP_BEDSIZE_CAT Hospital bedsize category 2016 Hospital
HOSP_CONTROL Control/ownership of hospital 2016 Hospital
HOSP_LOCATION Location (urban/rural) of hospital 2016 Hospital
HOSP_LOCTEACH Location/teaching status of hospital 2016 Hospital
HOSP_NASS NASS hospital number 2016 Enncounter, Hospital, Supplemental
HOSP_REGION Region of hospital 2016 Hospital
HOSP_TEACH Teaching status of hospital 2016 Hospital
I10_DXn ICD-10-CM Diagnosis 2016 Encounter
I10_NDX Number of ICD-10-CM diagnoses on this discharge 2016 Encounter
KEY_NASS HCUP NASS record identifier 2016 Encounter, Supplemental
N_DISC_U Number of discharges in the universe for the stratum 2016 Hospital
N_HOSP_U Number of hospitals in the universe for the stratum 2016 Hospital
NASS_STRATUM NASS sample stratum 2016 Hospital
NCPT_INSCOPE Number of in-scope surgeries for this encounter 2016 Encounter
NCPT_NOTINSCOPE Number of out-of-scope surgeries for this encounter 2016 Supplemental
PAY1 Expected primary payer, uniform 2016 Encounter
PL_NCHS Patient Location: NCHS Urban-Rural Code 2016 Encounter
S_DISC_U Number of discharges in the sample for the stratum 2016 Hospital
S_HOSP_U Number of hospitals in the sample for the stratum 2016 Hospital
TOTAL_AS_ENCOUNTERS AS encounters with at least one narrow surgery 2016 Hospital
TOTCHG Total charges, cleaned 2016 Encounter
YEAR Calendar year 2016 Encounter, Hospital, Supplemental
ZIPINC_QRTL Median household income for patient's ZIP Code (based on current year) 2016 Encounter
Check the corresponding boxes and then click

Internet Citation: NASS Description of Data Elements. Healthcare Cost and Utilization Project (HCUP). August 2019. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/db/nation/nass/nassdde.jsp.
Are you having problems viewing or printing pages on this Website?
If you have comments, suggestions, and/or questions, please contact hcup@ahrq.gov.
Privacy Notice, Viewers & Players
Last modified 8/21/19