Codes and Frequencies
For sample persons under age 18 who were ever hospitalized, OPHOSP1 reports the classification of the first operation performed on the person during hospitalization.
The NHIS uses only the first two digits of the ICD-9-CM Volume 3 codes used within hospitals for hospital record-keeping. The two-digit reporting preserves information on the body system or region on which the operation was performed but excludes details about the specific type of operation.
- 1981: Sample persons under age 18 who were ever hospitalized.
- 1981 : SAMPWEIGHT