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NEDS Description of Data Elements

NDX - Number of ICD-9-CM diagnoses on this discharge
Documentation Sections:
General Notes
Uniform Values
State Specific Notes
General Notes

NDX indicates the total number of ICD-9-CM diagnoses (valid and invalid) coded on the discharge record. In assigning NDX, the first listed diagnosis is included in the count, even if it is blank, so long as there is a secondary diagnosis present (see table below).

For data beginning in the fourth quarter of 2015, the count of the number of diagnoses is stored in the data element I10_NDX to indicate the implementation of the ICD-10-CM/PCS coding system.

Value Description
0 No diagnoses are coded on the record
1 Only the first listed diagnosis (DX1) is coded. All secondary diagnoses are blank.
2 One secondary diagnosis (DX2) is coded. The first listed diagnosis (DX1) may be coded or blank.
3 The second and third diagnoses (DX2 and DX3) are coded. The first listed diagnosis (DX1) may be coded or blank.

Uniform Values
VariableDescriptionValueValue Description
NDXNumber of ICD-9-CM diagnoses on this discharge0 - nnNumber of diagnoses
State Specific Notes

California (SEDD)

In quarter one (Q1) of 2008, 11 of the 330 hospitals did not report secondary diagnoses for any of the ED visits. In Q1 2008, about 93,000 records have only 1 diagnosis in these 11 hospitals. In quarter two through four of 2008, about 48,000 records per quarter have only 1 diagnosis reported in these 11 hospitals. We therefore estimate that about 45,000 records are missing secondary diagnoses in the 11 hospitals. This is less than 2 percent of the 2.3 million discharges in Q1 in the State and less than 0.5 percent of the 9.0 million discharges for the year. These hospitals can be identified by doing a frequency on NDX by DSHOSPID and DQTR.


Internet Citation: HCUP NEDS Description of Data Elements. Healthcare Cost and Utilization Project (HCUP). May 2015. Agency for Healthcare Research and Quality, Rockville, MD.
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Last modified 5/8/15