blood high density lipoprotein cholesterol level serum high density lipoprotein cholesterol level 2010-11-12T09:46:16Z CMO:0000361 Measurement of the amount of cholesterol, a eukaryotic sterol that in higher animals is the precursor of bile acids and steroid hormones and a key constituent of cell membranes, 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:0000184 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 mshimoyama serum HDL level serum HDL-C level serum cholesterol level