clinical measurement blood lipid measurement blood low density lipoprotein cholesterol level CMO:0000053 EFO:0004611 blood LDL level 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 low-density lipoprotein (LDL) molecules in a specified volume of blood, the fluid that circulates through the heart, arteries, capillaries and veins carrying nutrients and oxygen to the body tissues and metabolites away from them. LDL constitute a class of relatively large, heterogeneous lipoprotein particles, complex molecules that consist of a protein membrane surrounding a core of lipids. The LDL class of lipoproteins has a density between 1.019 and 1.063 g/ml. In some animal species, such as canine and rodents, this may overlap with the HDL1 class and be designated LDL/HDL1. EFO:0007804 clinical_measurement_ontology LDL cholesterol change measurement 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. low density lipoprotein cholesterol measurement blood LDL-C level