blood intermediate density lipoprotein cholesterol level serum intermediate density lipoprotein cholesterol level 2013-05-08T11:11:20Z CMO:0001564 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 serum, the clear liquid that separates from blood after it has clotted completely, i.e. blood plasma from which fibrinogen has been removed. IDL are relatively large lipoprotein particles (complex molecules that consist of a protein membrane surrounding a core of lipids) formed by degredation 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. VT:0010503 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 jsmith serum IDL level serum IDL-C level serum cholesterol level