The primary reason a doctor orders a test to determine the iron level in a patient's blood is to determine how his body stores iron. If the levels are low, the patient may be anemic. If it is too high, his body may be retaining too much iron. Certain cancers, rheumatoid arthritis, liver disease and hyperthyroidism also cause high iron levels in the blood, according to Mayo Clinic.
Iron deficiency anemia is a condition that makes it difficult to get enough oxygen to the body. Iron is essential to the production of hemoglobin. Hemoglobin is the substance in red blood cells that transports oxygen to the cells. The most common cause of anemia in humans is iron deficiency, according to WebMD.
Heavy menstrual bleeding in women, dietary deficiencies, internal bleeding and an iron absorption problem in the intestines are common causes of low iron levels. Anemic individuals feel short of breath or weak. They often have headaches and find it difficult to concentrate. WebMD indicates they often look pale and are cranky or grumpy.
If the iron levels in the blood are too high, the doctor orders other tests to determine the cause of the abnormality. If the levels are high, it is essential to talk with the doctor to determine the meaning of the test results, according to WebMD.