Spike duplicate

A spike duplicate, as defined by the United States Environmental Protection Agency via its SEDD Specification Version 5.2, is "a second reanalysis of a regular sample done for quality control purposes with a known spike added." The EPA adds that the "data is expected to include an original client sample ID, and, potentially, a percent recovery, an RPD, and an expected result for each analyte where the analyte type 'spike.' The original client sample ID identifies the regular sample that was spiked and reanalyzed. There should be another sample plus method node with quality control category 'spike' with the same client method ID and original client sample ID."