What Is a Ferritin Blood Test?

QUESTION: My doctor sent me to a lab for a blood test. The slip was marked
"ferritin". Can you tell me what this ferritin is and why this test would be
ordered in a patient?
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ANSWER: Ferritin is a large molecule containing variable amounts of iron and
most of the iron which is stored in the body and used to build hemoglobin is
composed of ferritin. This ferritin is usually stored in liver cells.
Doctors use laboratory tests for ferritin to determine whether or not a
patient has sufficient iron reserves in their system, and sufficient supplies
to produce hemoglobin. A low serum ferritin concentration indicates iron
deficiency and probably is one of the best tests for identifying this
condition. When ferritin values are high, it may be an indication of liver
injury, and in some cases, of a neoplasm and therefore must be interpreted
with great care. For you to be properly informed about your situation, you
will have ask your own doctor.