[A unit of mass concentration defined as the concentration of one milligram of a substance in unit volume of the mixture equal to one cubic deciliter or 100 cubic centimeters. It is also a unit of mass density (volumic mass) defined as the density of substance which mass equal to one milligram occupies the volume one cubic deciliter or 100 cubic centimeters. ( NCI )] (UMLS (NCI) C0439269) =Quantitative Concept