serum phospholipid level blood high density lipoprotein phospholipid level serum high density lipoprotein phospholipid level 2013-05-08T12:54:24Z CMO:0001567 JSmith Measurement of the amount of phospholipid, any of various phosphorus-containing lipids that are composed mainly of fatty acids, a phosphate group, and a simple organic molecule such as glycerol, carried in high-density lipoprotein (HDL) molecules in a specified volume of serum, the clear liquid that separates from blood after it has clotted completely, i.e. blood plasma from which fibrinogen has been removed. HDL is the smallest of the major lipoprotein particles, complex molecules that consist of a protein membrane surrounding a core of lipids. The HDL class of lipoproteins, specifically the subtypes of HDL2 and HDL3, have densities between 1.063 and 1.210 g/ml. VT:0010504 Values for density ranges of the lipoprotein classes are approximate. The classes may be defined differently by different researchers, in part because class definitions depend on the number of subclasses into which the lipoprotein fractions are divided. clinical_measurement_ontology serum HDL phospholipid level