Serum iron is a test that measures how much iron is in your blood.
How the Test is Performed
A blood sample is needed.
Iron levels are highest in the morning. Your doctor will likely have you do this test in the morning.
How to Prepare for the Test
Certain medicines may affect the results of this test. Your doctor will tell you if you need to stop taking any medicines. Do not stop any medicine before talking to your doctor.
Medicines that can affect the test result include:
- Birth control pills and estrogens
- Blood pressure drugs
- Cholesterol drugs
- Deferoxamine (removes excess iron from the body)
- Gout drugs
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
Your doctor may order this test if you have signs of low iron (iron deficiency) or too much iron.
- Iron: 60-170 mcg/dL (micrograms per deciliter)
- TIBC: 240-450 mcg/dL
- Transferrin saturation: 20-50%
Note: mcg/dl = micrograms per deciliter
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
Higher-than-normal iron level may mean:
- Too much iron in the body (hemochromatosis)
- Breakdown of red blood cells (hemolysis)
- Anemia due to red blood cells being destroyed too quickly (hemolytic anemia)
- Liver tissue death (hepatic necrosis)
- Inflammation of the liver (hepatitis)
- Vitamin B-12 deficiency, vitamin B-6 deficiency
- Iron poisoning
- Many blood transfusions
Lower-than-normal levels may mean:
- Long-term digestive tract bleeding
- Heavy menstrual bleeding
- Intestinal conditions that cause poor absorption of iron
- Not enough dietary iron
Other conditions for which the test may be performed:
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Fe+2; Ferric ion; Fe++; Ferrous ion; Iron - serum
Brittenham GM. Disorders of iron homeostasis: iron deficiency and overload. In: Hoffman R, Benz EJ Jr, Silberstein LE, et al., eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap 34.
Elghetany MT, Banki K. Erythrocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 32.
Update Date 2/24/2014
Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team. .