Table I.

Overview of the elements of an SI-reference measurement system, with indication of the related tasks and responsibilities.

Element	Organization	Task
SI-Unit	Conférence Générale des Poids et Mesures (CGPM)	Establishment of a coherent system of units (mol)
Component (analyte)	IFCC	Definition of the relevant component
Reference material	National Metrology Institutes; IRMM, NIST	Realization of SI units. Production and certification of reference material
Reference measurement procedure	Reference laboratory or other competent analytical laboratory	Development and validation of reference measurement procedures
Reference laboratory	No representative organization (“Networks”)	Application of the reference measurement procedures