PAY1_X retains the expected primary payer as provided by the data source. The original values have not been recoded into uniform HCUP values and are source-specific.

Two HCUP data elements contain uniformly coded information about the expected primary payer:

• PAY1 has general categories for Medicare, Medicaid, private insurance, and other payers.
• PAY1_N has more detailed categories for private insurance and other payers. PAY1_N is only available in the 1988-1997 HCUP databases. This data element is discontinued beginning in the 1998 data because of the difficulty of coding the information uniformly across States.

Information on the definition of the source values contained in PAY1_X and how the source values are recoded into the HCUP uniform variable PAY1 is available under the note for expected primary payer PAY1.

PAY1_X is included in the NIS beginning in 1998.