Iron is an essential nutrient that plays a vital role in many biochemical processes. There are four main blood tests used to assess iron levels, including serum iron, ferritin, total iron binding capacity and transferrin saturation. Serum iron is the most commonly used test, as it provides a direct measure of the amount of iron circulating in the blood. Ferritin is a protein that stores iron, and levels can be elevated in cases of inflammation or liver disease. Total iron binding capacity is a m