Summary

• This test measures the amount of iron in serum, the liquid portion of your blood.
• It is one of a group or panel of blood tests called Iron Studies that together look at how much iron is in your blood and body.
• The amount of iron that circulates in the blood varies throughout the day.
• This means that measuring iron alone is rarely helpful and it needs to be combined with other tests to get an accurate picture of your iron status.
• The serum iron test is most useful in calculating transferrin saturation. A transferrin saturation test shows how much iron is bound to transferrin. This helps show the amount of iron that can be transported in your blood.

Assessing your iron status

This test measures the amount of iron in serum, the liquid portion of your blood. Testing iron alone is not useful in assessing how much iron is in your blood or being stored in your body. This is because the amount of iron in your blood varies throughout the day.

For this reason, a group of tests is performed called Iron Studies. Usually, this includes:

• Ferritin
• Serum iron
• Transferrin
• Transferrin saturation or Total iron binding capacity (TIBC).

Each test measures a different aspect of the storage and transportation of iron in the blood. By assessing each result, your doctor can build up a picture of your overall iron status.

For a full account of how your iron levels will be tested go to Iron Studies.

What is iron and why do we need it?

Your body needs iron for daily activities, growth and development. It uses iron to make haemoglobin in red blood cells. Red blood cells carry oxygen through the bloodstream from the lungs and release it to where it is needed in the body. 

Our bodies cannot make iron. It must be absorbed from our diet or from supplements. The amount of iron we absorb is decided by our body's needs. We normally use just a little bit of iron each day and we don’t have a way of getting rid of excess iron. Instead, the body closely controls iron levels by regulating how much iron is absorbed from our food.

If your iron levels are too low, your body will not be able to make enough haemoglobin to function properly. This condition is known as iron-deficiency anaemia. It is also possible to have too much iron, which is known as iron overload, and it may be caused by several conditions including an inherited condition called haemochromatosis and chronic liver disease, as well as regular blood transfusions.

How iron is taken up and used

• Iron is absorbed from your food into the bloodstream through your small intestine. Once the iron enters the blood, it sticks to a protein called transferrin. Transferrin transports it to various tissues throughout the body.
• Iron is stored in a protein called ferritin. This is found all over your body but mainly in the liver. Ferritin releases iron as it is needed when your body detects low iron levels in your blood.  
• Entering the bloodstream, iron once again sticks to transferrin, and it travels to the bone marrow where new blood cells are made.
• Here it is taken up by newly forming red blood cells which have transferrin receptors on their surface.  Entering through the receptor it moves into the cell where the iron is separated from the transferrin and then incorporated into haemoglobin.

Since red blood cells live for an average of about 120 days, the body needs a constant supply of iron to maintain haemoglobin levels. Dying red blood cells are recycled and old haemoglobin is broken down and iron is re-used.

Why get tested?

If it is suspected that you have too little or too much iron in your blood and body, your medical team may first request a full blood count (FBC), which gives information on the number, size and shape of your red blood cells and how much haemoglobin is in the blood. If the FBC suggests iron deficiency, iron studies will be requested as the next investigation.

Having the test

Sample

Serum iron is measured on a blood sample, usually taken from a vein in the arm.

Any preparation?

None.

Your results

Reading your test report

Your results will be presented along with those of your other tests on the same form.  You will see separate columns or lines for each of the tests that make up the iron studies panel.

Testing your iron alone is not a good measure of how much iron is in your blood or being stored in your body. For this reason, a group of tests called Iron Studies will usually be done to assess your iron status.

Reference intervals

Your results will be compared to reference intervals (sometimes called a normal range). 

• Reference intervals are the range of results expected in most healthy people of the same age and sex. 
• Your results may be flagged high or low if they sit outside this range.
• Many reference intervals vary between labs so only those that are standardised or harmonised across most laboratories are given on this website.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. Blood test results must be interpreted with an understanding of your own particular symptoms and clinical situation.  For this reason, your results are best interpreted by your own doctor.

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How will the results from this test change the course of my care?
• What will happen next, after the test?

More information

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.

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