Apolipoprotein B (ApoB) is a protein that plays a crucial role in lipid metabolism. It is the primary protein component of lipoproteins, which transport fats and cholesterol in the bloodstream. There are two main forms of ApoB: ApoB-100, found in low-density lipoproteins (LDL), and ApoB-48, found in chylomicrons. ApoB is essential for the formation and secretion of these lipoproteins, influencing how fats are distributed throughout the body. Elevated levels of ApoB are associated with an increased risk of cardiovascular diseases, making it an important marker for assessing heart health and metabolic conditions.