This test is used to measure the levels of iron stored in the body. This test is usually ordered when a physician believes a patient has low iron levels which can cause issues like anemia. Iron is a power house when it comes to the body. It’s a super nutrient, one that keeps the cells of the body working properly. Iron can help you concentrate and is in control of your body's energy levels. If you have an iron deficiency, you may feel like you want to take a nap all the time, and no matter how many snoozes you have - you still want more!