Transferrin

You get iron from eating food or taking supplements. There are iron-only supplements, but many multivitamin/mineral supplements also contain iron. Most people in the United States get enough iron. However, certain people may be more likely to have trouble getting enough iron. Iron levels that are too low or too high can cause health concerns. Not having enough iron is the most common cause of anemia.

There are different types of iron tests, including a serum iron test, transferrin test (which measures transferrin, a protein that moves iron throughout your body), total iron-binding capacity (TIBC) test, and ferritin blood test. Because transferrin is the main protein that binds and carries iron in the blood, measuring it gives a direct picture of how much iron your blood can transport, which helps your provider assess your overall iron balance. The amount of iron in your blood varies throughout the day and may be higher in the morning.

You may need testing if you have symptoms of iron levels that are too low or too high. Symptoms of low iron include weakness or fatigue, dizziness, shortness of breath, and arrhythmia. Symptoms of high iron include weakness or fatigue, joint pain, abdominal pain, loss of interest in sex or erectile dysfunction, and skin color changes.

Your provider will consider your symptoms, age, medical history, and other blood test results to interpret iron tests.

Higher than normal transferrin usually means your body is trying to grab more iron than it has. This is the typical pattern in iron deficiency anemia.

Lower than normal transferrin can be seen in iron overload conditions such as hemochromatosis, in long-term illness or inflammation, in liver disease, in malnutrition, and in protein loss (such as nephrotic syndrome). Because transferrin drops with inflammation, it can sometimes look misleadingly low even when iron stores are fine.

Low iron levels may indicate iron deficiency anemia, another type of anemia, or thalassemia, an inherited blood disorder.

High iron levels may indicate hemochromatosis, lead poisoning, or liver disease.

Most conditions causing too little or too much iron can be treated with supplements, dietary changes, medicines, and other therapies.

Not all abnormal results indicate a medical condition needing treatment. Some medicines, including birth control pills and estrogen treatments, can affect iron levels.