At a Glance
Why Get Tested?
To determine your blood iron level. Testing for blood iron levels is part of a series of tests to assess iron body stores and the impact of low iron on anaemia (low haemoglobin). The serum iron level varies markedly throughout the day and according to recent intake, it is not helpful and should not be used as a stand-alone test in the diagnosis of iron deficiency anaemia.
When to Get Tested?
If your doctor thinks that you might have too little or too much iron in your blood. Low iron can cause anaemia, and is usually due to long-term or heavy bleeding, pregnancy, or rapid growth (in children); rarely is it due to poor diet. A high level of circulating iron may be due to ingestion of an overdose of iron (usually in children). A high level of stored iron, measured most accurately by ferritin, can be due to a genetic condition, extensive blood transfusions, or rarely, ingestion of excess amounts of iron over a long period.
A blood sample drawn from a vein in your arm
Test Preparation Needed?
You may be instructed to fast for 12 hours before the test, in this case only water is allowed.
The Test Sample
What is being tested?
Iron is an essential trace element in your blood. It is necessary for forming healthy red blood cells, which carry oxygen through your body, and for some enzymes, which perform tasks in your body.
If anaemia is suspected the first test required is a full blood examination. This provides information about the amount of haemoglobin (low in anaemia), size of the red blood cells (small in iron deficiency anaemia and some other conditions) and other useful measures to provide clues about the cause of the anaemia. If iron deficiency is suggested from the full blood examination, then iron studies will be performed. Iron studies include iron, ferritin, transferrin and transferrin saturation. Sometimes the specialised test, soluble transferrin receptor may be requested.
How is the sample collected for testing?
A blood sample is drawn by needle from a vein in your arm.
Is any test preparation needed to ensure the quality of the sample?
You may be asked to fast for 12 hours in which case only water is allowed.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Pasricha S et al (2010) Diagnosis and management of iron deficiency anaemia: a clinical update Medical Journal of Australia 193: 525-532