Iron is a mineral in your body that comes from foods like red meat and fortified cereals or from supplements you take. You need iron to make red blood cells. Iron is also an important part of hemoglobin, a protein in your blood that helps carry oxygen from your lungs to the rest of your body.
An iron test can show if you have too much or too little of this mineral in your system. It can check for conditions like anemia, or iron overload (excess iron). Your doctor might order a test if you have symptoms of either condition.