blood high density lipoprotein cholesterol level plasma high density lipoprotein cholesterol level 2011-11-03T03:14:50Z CMO:0000646 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 plasma, the fibrinogen-containing fluid portion of the blood in which the particulate components are suspended. 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 plasma HDL level plasma HDL-C level plasma cholesterol level