Serum is used in numerous diagnostic tests as well as blood typing. Serum does not contain white blood cells ( leukocytes), red blood cells ( erythrocytes), platelets, or clotting factors. Serum includes all proteins not used in blood clotting all electrolytes, antibodies, antigens, hormones and any exogenous substances (e.g., drugs or microorganisms). It may be defined as blood plasma without the clotting factors, or as blood with all cells and clotting factors removed. Serum ( / ˈ s ɪər ə m/) is the fluid and solute component of blood which does not play a role in clotting. Preparation of serum cups for a lipids panel designed to test cholesterol levels in a patient's blood
