What Is a Serum Iron Test?
A serum iron test measures
how much iron is in your serum. Serum is
the liquid that is left over from your blood when red blood cells and clotting factors
have been removed.
The serum iron test can reveal abnormally low or high blood
iron levels. Your doctor will most likely order this test after another lab
test shows an abnormal result.
Having too much iron — or not enough — can cause serious
health problems. This test will help your doctor give you a more accurate
The Serum Iron Test
A nurse will insert a needle into a vein in your arm or hand
and draw a small sample of blood. This sample will then be tested in a
Your doctor may ask you to fast beginning at midnight the
night before the procedure. Morning is the best time to conduct this test
because that’s when your iron levels are highest.
What Does a Serum Iron Test Check For?
Serum iron is not a routine test. It’s usually ordered as a
follow-up when a more common test reveals abnormal results. Such tests include complete blood count or hemoglobin test.
Your doctor may also order a serum iron test if you’re showing
symptoms of anemia. Abnormal iron tests could be a sign of iron deficiency or
Symptoms of Abnormal Iron Levels
Early symptoms of iron deficiency (anemia) include:
- chronic fatigue
- muscle weakness
You may develop other symptoms as your condition worsens.
These may include:
- difficulty concentrating
- tongue and mouth sores
- pica (the compulsion to eat non-food items, such
as paper or ice chips)
- misshapen nails
Symptoms of iron overload (when your body produces too much
- pain in your abdomen and joints
- bronzing or darkening of skin
- heart problems
- lack of energy
- lack of sex drive
- weight loss
- muscle weakness
These symptoms generally get worse as your condition
Normal Serum Iron Test Results
Serum iron is measured in micrograms of iron per deciliter
of blood (mcg/dL). The following are considered normal ranges for a serum iron
- iron: 60 to 170 mcg/dL
- transferrin saturation: 25 percent to 35 percent
- Total iron binding capacity (TIBC): 240 to 450
Transferrin is a protein in the blood that transports iron
throughout your body. Examining how much iron is in the transferrin proteins
can tell your doctor if you have too much or too little iron in your blood.
TIBC measures how well the transferrin proteins are
transporting iron around your body.
Abnormal Serum Iron Test Results
Abnormally high iron serum levels may mean you’ve consumed
too much iron, vitamin B-6, or vitamin B-12. High levels of iron may indicate:
- hemolytic anemia or hemolysis: your body doesn’t
have enough healthy red blood cells
- liver conditions: such as hepatic necrosis (liver
failure) and hepatitis
- iron poisoning: you’ve taken more than the recommended
dose of iron supplements
- iron overload: your body naturally retains too
Abnormally low iron levels may mean you haven’t consumed
enough iron or your body isn’t absorbing the iron properly. Regularly having heavy
menstrual periods can also lead to low iron levels.
Low iron levels may also indicate:
- gastrointestinal blood loss
The Impact of Medications on Serum Iron Test Results
Many medications can affect the results of a serum iron test
by increasing or decreasing your iron levels. For example, birth control pills
are commonly used and can affect iron levels. Tell your doctor before the test
if you’re taking any medications.
Your doctor may instruct you to temporarily stop taking
medicines that will affect the test. If you can’t stop taking the medication,
your doctor will take the medication’s effects into account when interpreting
Risks of a Serum Iron Test
You’ll probably experience mild pain or a pricking sensation
when you have your blood drawn. You might also bleed slightly afterward or
develop a small bruise at the puncture site.
In rare cases, you might experience more serious
complications, such as:
- excessive bleeding
After a Serum Iron Test
Your doctor will review your results with you. They may
suggest iron supplements or diet changes, depending on the levels of iron in
Your doctor may
suggest eating more iron-rich foods if your iron levels are too low. Iron-rich
- red meats
- leafy, dark green vegetables
More tests may be needed before your doctor can diagnose you
with a health condition.