Blood Test: Ferritin (Iron)



Blood Test: Ferritin (Iron)



What It Is



A ferritin blood test helps doctors evaluate the amount of iron
stored in the body. The body uses iron to make hemoglobin, the
oxygen-carrying protein inside red blood cells.

Iron is obtained from food and stored for use as ferritin, an
iron-carrying protein. Ferritin is found mostly in the liver, but it's
also present in smaller amounts in the bone marrow, spleen, and muscles.
Only a small amount is normally present in the blood, but it can still
be used to estimate the body's total iron stores.

Stored iron is important because when iron intake is low, the body
relies on ferritin to release the iron it needs. If enough iron isn't
available in storage, a person will progress through several stages of
iron deficiency. If the situation isn't corrected, iron deficiency may
eventually lead to anemia — a decreased amount of hemoglobin in the
blood, resulting in difficulty delivering oxygen to the cells and
tissues.

Most iron deficiency cases in childhood are due to low iron intake —
for example, getting too few iron-rich foods such as red meat and
fortified cereals, or, in bottle-fed infants, switching from
iron-fortified formula to cow's milk before 12 months. Infants who are
breastfed tend to get enough iron from their mothers until about 4-6
months of age, when iron-fortified cereal is usually introduced.

Low iron also may be caused by poor iron absorption by the intestine
or by blood loss, most commonly from heavy menstruation or gradual blood
loss in the intestinal tract.

Some health conditions can result in too much iron and ferritin in
the body (iron overload). The most common is hemochromatosis, a genetic
disease in which too much iron is absorbed.

Why It's Done



Doctors may order ferritin test when they suspect kids have too
little or too much iron in their bodies. This suspicion is often based
on the results of routine blood tests, such as a complete blood counts,
that show low hemoglobin levels.

Other times, doctors may suspect problems with iron levels based on
certain symptoms. Early symptoms if iron depletion or deficiency might
be subtle. But once levels drop below a certain amount, kids might
experience symptoms such as fatigue, weakness, pale skin, rapid
heartbeat, or dizziness. The most common symptoms of iron overload are
joint pain, chronic fatigue, and abdominal pain.

Ferritin levels are a helpful first indicator of abnormal iron stores
because they tend to drop or rise even before symptoms occur. They are
also not as prone to dietary fluctuations as blood iron levels.

Preparation



No special preparations are needed for this test. On the day of the
test, it may help to have your child wear a short-sleeve shirt to allow
easier access for the technician who will be drawing the blood.The Procedure



A health professional will usually draw the blood from a vein. For an
infant, the blood may be obtained by puncturing the heel with a small
needle (lancet). If the blood is being drawn from a vein, the skin
surface is cleaned with antiseptic and an elastic band (tourniquet) is
placed around the upper arm to apply pressure and cause the veins to
swell with blood. A needle is inserted into a vein (usually in the arm
inside of the elbow or on the back of the hand) and blood is withdrawn
and collected in a vial or syringe.

After the procedure, the elastic band is removed. Once the blood has
been collected, the needle is removed and the area is covered with
cotton or a bandage to stop the bleeding. Collecting the blood for the
test will only take a few minutes.



What to Expect



Either method (heel or vein withdrawal) of collecting a blood sample
is only temporarily uncomfortable and can feel like a quick pinprick.
Afterward, there may be some mild bruising, which should go away in a
day or so.

Getting the Results



The blood sample will be processed by a machine. The results are commonly available within 1-2 days.

Risks



The ferritin test is considered a safe procedure. However, as with
many medical tests, some problems can occur with having blood drawn:

• fainting or feeling lightheaded
  
• hematoma (blood accumulating under the skin causing a lump or bruise)
  
• pain associated with multiple punctures to locate a vein
  

Helping Your Child



Having a blood test is relatively painless. Still, many children are
afraid of needles. Explaining the test in terms your child can
understand might help ease some of the fear.

Allow your child to ask the technician any questions he or she might
have. Tell your child to try to relax and stay still during the
procedure, as tensing muscles and moving can make it harder and more
painful to draw blood. It also may help for your child to look away when
the needle is being inserted into the skin.

If You Have Questions



If you have questions about the ferritin test, speak with your doctor. You can also talk to the technician before the procedure.