blood intermediate density lipoprotein cholesterol level plasma intermediate density lipoprotein cholesterol level 2013-05-08T11:09:43Z CMO:0001563 JSmith This is a 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 intermediate-density lipoprotein (IDL) molecules in a specified volume of plasma, the fibrinogen-containing fluid portion of the blood in which the particulate components are suspended. IDL are relatively large lipoprotein particles (complexes that consist of protein surrounding a core of lipids) formed by degradation of very low density lipoproteins (VLDL) particles and thus having a size intermediate between those of VLDL and low density lipoproteins. The IDL class of lipoproteins is defined as having a density between 1.006 and 1.019 g/ml. 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 plasma IDL cholesterol level plasma IDL-C level plasma cholesterol level