PAY1_N (where _N indicates nonuniform) preserves much of the original expected primary payer detail from the various data sources. However, some categories of PAY1_N are not available from some sources because not all sources have the same level of detail available.

The HCUP data element PAY1 contains more general categories for commercial and other payers. PAY1_X retains the expected primary payer as provided by the data source. The data element PAY1_N was discontinued in 1998.