Non-high-density lipoprotein (N-HDL) cholesterol is a simple calculated value that subtracts the level of good cholesterol (HDL-C) from total cholesterol. This value represents the total amount of cholesterol present in all "bad" or atherosclerotic lipoproteins, which include LDL (bad), VLDL, IDL (medium), and chylomicrons. Due to its comprehensive nature, it has become an important secondary therapeutic target in lipid management guidelines.