NCIt definition : A unit of mass concentration defined as the concentration of one nanogram of a substance
per unit volume of the mixture equal to one deciliter. The concept also refers to
the unit of mass density (volumic mass) defined as the density of substance which
mass equal to one nanogram occupies the volume of one deciliter.;
Alternative definition : CDISC: A unit of mass concentration defined as the concentration of one nanogram of
a substance in unit volume of the mixture equal to one deciliter. The concept also
refers to the unit of mass density (volumic mass) defined as the density of substance
which mass equal to one nanogram occupies the volume one deciliter.(NCI);