Serum iron test

Definition

A serum iron test measures how much iron is in your blood.

Alternative Names

Fe+2; Ferric ion; Fe++; Ferrous ion; Iron - serum; Anemia - serum iron; Hemochromatosis - serum iron

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

Iron level can change, depending on how recently you ingested iron. Your health care provider will likely have you do this test in the morning or after fasting.

Certain medicines may affect the results of this test. Your provider will tell you if you need to stop taking any medicines. DO NOT stop any medicine before talking to your provider.

Medicines that can affect the test result include:

• Antibiotics
• Birth control pills and estrogens
• Blood pressure drugs
• Cholesterol drugs
• Deferoxamine (removes excess iron from the body)
• Gout drugs
• Testosterone

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 provider may recommend this test if you have:

• Signs of low iron (iron deficiency)
• Signs of too much iron
• Anemia caused by a chronic disease

Normal Results

Normal value range is:

• Iron: 60 to 170 micrograms per deciliter (mcg/dL), or 10.74 to 30.43 micromoles per liter (micromol/L)
• Total iron binding capacity (TIBC): 240 to 450 mcg/dL, or 42.96 to 80.55 micromol/L
• Transferrin saturation: 20% to 50%

The numbers 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 provider about the meaning of your specific test results.

What Abnormal Results Mean

Higher-than-normal iron level may be a sign of:

• Too much iron in the body (hemochromatosis)
• Anemia due to red blood cells being destroyed too quickly (hemolytic anemia)
• Liver tissue death
• Inflammation of the liver (hepatitis)
• Iron poisoning
• Frequent blood transfusions

Lower-than-normal level may be a sign of:

• Long-term digestive tract bleeding
• Heavy menstrual bleeding
• Intestinal conditions that cause poor absorption of iron
• Not enough iron in the diet
• Pregnancy

Risks

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person 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 lightheaded
• Multiple punctures to locate veins
• Hematoma (blood buildup under the skin)
• Infection (a slight risk any time the skin is broken)

References

Brittenham GM. Disorders of iron homeostasis: iron deficiency and overload. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 36.

Bunn HF. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 158.

Chernecky CC, Berger BJ. Iron (Fe) – serum. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:690-691.