Ferric ion
Key points
- Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand.
- For infants and children: The preparation you can provide for this procedure depends on your child's age, previous experiences, and level of trust.
- About 65% of the iron in the body is found in hemoglobin (in red blood cells) and about 4% in myoglobin (in skeletal muscle).
- Special considerations Drugs that can increase iron measurements include chloramphenicol, estrogens, oral contraceptives, and methyldopa.
Alternative names
Fe+2; Serum iron; Fe++; Ferrous ion; Iron - serum
Definition
A test that measures the amount of iron in the blood.
How the test is performed
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.
In an infant or young child:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How to prepare for the test
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:
- infant test or procedure preparation (birth to 1 year)
- toddler test or procedure preparation (1 to 3 years)
- preschooler test or procedure preparation (3 to 6 years)
- schoolage test or procedure preparation (6 to 12 years)
- adolescent test or procedure preparation (12 to 18 years)
How the test will feel
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
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.
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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