Also known as
Iron indices, iron tests

Iron Studies is a group of tests used to assess the levels of iron in the body.
When to get tested
If you have signs or symptoms that suggest you may have too little iron (deficiency, anaemia) or too much iron (such as haemochromatosis).

Iron is needed to form haemoglobin, the red component of red blood cells that carry oxygen around the body. The body has no way of getting rid of excess iron and it controls iron levels by absorbing just the right amount from food. The small amount we use up in daily living must be matched by the amount we take in. The mechanism for regulating iron levels is finely tuned. If we lose blood we need to make up the iron that is lost. Iron levels are often tested when it is suspected that someone has internal bleeding, such as from ulcers or tumours. Low iron levels can also occur when the body cannot use iron properly such as in certain cancers, autoimmune diseases and chronic infections.

The most common cause of too much iron is an inherited genetic condition, haemochromatosis. It is caused by a mutation in a gene that controls the amount of iron absorbed from food. The body behaves as if it’s in a constant state of iron deficiency and absorbs more iron than it needs. Iron gradually accumulates, causing organ damage over many years.
Sample required
A blood sample drawn from a vein in your arm
Test preparation needed
What results can show
Iron studies can include several tests. The most common are:
  • Serum iron measures the level of iron in the liquid part of your blood. (Iron testing uses blood serum rather than whole blood, because this is where these substances are dissolved.)
  • Transferrin is a protein that transports iron around the body. Normally, transferrin is typically one-third saturated with iron.
  • Transferrin saturation is calculated from the iron and transferrin results and represents the amount of iron that has been attached to transferrin as a percentage of transferrin's total iron carrying capacity. It is a more accurate indicator of the amount of iron in the body than either serum iron or serum transferrin alone.
  • Ferritin This is another protein that attaches to iron. The amount of ferritin in the blood serum is the best measure of the amount of iron stored in the body (mainly in the liver).

In the early stage of iron deficiency there is still enough iron to make red cells but without adequate replacement the stores are used up. The serum iron level may be normal in this stage but the ferritin level will be low. Eventually, all the stored iron is used and the body tries to compensate by producing more transferrin to increase iron transport. The serum iron level continues to decrease and transferrin increases.

Iron Studies is often ordered together with the Full Blood Count. The results of all these tests need to be considered together along with your symptoms. For more details about Iron Studies see our video.