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Alternative names Return to top
Fe+2; Ferric ion; Fe++; Ferrous ion; Iron - serumDefinition Return to top
A test that measures the amount of iron in the blood.How the test is performed Return to top
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.How to prepare for the test Return to top
For adults, no specific preparation is required.
For infants and children:
The preparation you can provide for this procedure depends on your child's age, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics:
How the test will feel Return to top
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.Why the test is performed Return to top
This test is performed when iron deficiency is suspected.
About 65% of the iron in the body is found in hemoglobin (in red blood cells) and about 4% in myoglobin (in skeletal muscle). About 30% of the iron in the body is stored (as ferritin or hemosiderin) in the liver, bone marrow, and spleen. A small percentage of the body's iron is in transport between various parts of the body or is a component of proteins in cells throughout the body.
The body efficiently conserves iron so that only about 1 mg (men and post-menopausal women) or 1.8 mg (premenopausal adult women) is lost per day in the urine or menstrual blood. Since only about 10-15% of the iron we eat in our food is absorbed, even under optimum circumstances, the recommended daily allowance for iron is 10 mg (men and post-menopausal women) and 18 mg (premenopausal adult women). Pregnancy greatly increases the need for iron, and iron deficiency is most common in women of reproductive age.
Serum iron, as measured in the laboratory, is really transferrin-associated ferric iron. Each transferrin molecule can carry 2 iron atoms. Normally about 30% of the available sites are filled. This is called the percent transferrin saturation. By completely saturating all the available binding sites, it is possible to measure the total iron binding capacity (TIBC). This is really a measure of the transferrin in the serum. TIBC and percent transferrin saturation are usually measured at the same time serum iron is measured.
Normal Values Return to top
What abnormal results mean Return to top
Higher-than-normal levels may indicate:What the risks are Return to top
Special considerations Return to top
Drugs that can increase iron measurements include chloramphenicol, estrogens, oral contraceptives, and methyldopa.
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Page last updated: 28 October 2004 |