Table 1.

Description of Metabolon QC samples

Type	Description	Purpose
MTRX	Large pool of human plasma maintained by Metabolon that has been characterized extensively	Assure that all aspects of Metabolon process are operating within specifications
CMTRX	Pool created by taking a small aliquot from every customer sample	Assess the effect of a nonplasma matrix on the Metabolon process and distinguish biological variability from process variability
PRCS	Aliquot of ultrapure water	Process Blank used to assess the contribution to compound signals from the process
SOLV	Aliquot of solvents used in extraction	Solvent blank used to segregate contamination sources in the extraction