Serum iron

Definition

Serum iron is a test that measures how much iron is in your blood.

Alternative Names

Fe+2; Ferric ion; Fe++; Ferrous ion; Iron - serum

How the test is performed

A blood sample is needed. For information on how this is done, see: Venipuncture

Iron levels are highest in the morning. It's best to do this test in the morning.

How to prepare for the test

Make sure your doctor knows about all the medications your are taking.

Drugs that can increase iron include estrogens, birth control pills, and methyldopa.

Drugs that can lower iron include cholestyramine, colchicine, deferoxamine, methicillin, allopurinol, and testosterone.

How the test will feel

When the needle is inserted to draw blood, some people feel moderate pain. Others will feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed

Your doctor may order this test if you have signs of low iron (iron deficiency).

Normal Values

  • Iron: 60-170 mcg/dL
  • TIBC: 240-450 mcg/dL
  • Transferrin saturation: 20-50%

Note: mcg/dl = micrograms per deciliter

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What abnormal results mean

Higher-than-normal levels may mean:

  • Hemochromatosis
  • Hemolysis
  • Hemolytic anemias
  • Hemosiderosis
  • Liver tissue death (hepatic necrosis)
  • Hepatitis
  • Vitamin B-12 deficiency, vitamin B-6 deficiency
  • Iron poisoning
  • Many blood transfusions

Lower-than-normal levels may mean:

  • Chronic gastrointestinal blood loss
  • Chronic heavy menstrual bleeding
  • Poor absorption of iron
  • Not enough dietary iron
  • Pregnancy

Other conditions under which the test may be performed:

  • Anemia of chronic disease

What the risks are

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)

Special considerations

References

Ginder G. Microcytic and hypochromic anemias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 162.

Yee DL, Bollard CM, Geaghan SM. Appendix: Normal Blood Values: Selected Reference Values for Neonatal, Pediatric, And Adult Populations. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 164.