At a Glance
Why Get Tested?
To evaluate your body's current store of iron
When to Get Tested?
When your doctor suspects that you may have too little or too much iron in your system
A blood sample taken from a vein in your arm
Test Preparation Needed?
Your doctor may request that you fast for 12 hours prior to some iron blood tests; in this case, only water is permitted.
The Test Sample
What is being tested?
Iron is an essential nutrient. It is needed in small quantities to help form normal red blood cells (RBCs). Iron is a critical part of haemoglobin, the protein in red blood cells that binds oxygen in the lungs and releases it as blood travels to other parts of the body. Low iron levels can lead to anaemia and the production of RBCs that are small (microcytic) and pale (hypochromic). Large quantities of iron can be toxic to the body, and absorption of too much iron over time can lead to the accumulation of iron compounds in organs and tissues. This can damage organs such as the liver, heart, and pancreas.
Iron is normally absorbed from food and transported throughout the body bound to transferrin, a protein produced by the liver. About 70% of the iron transported is incorporated into the haemoglobin inside RBCs. Most of the rest is stored in the tissues as ferritin or haemosiderin. Small amounts of iron are used to produce other proteins such as myoglobin (the oxygen carrying protein in muscle), and some enzymes.
Iron tests evaluate the amount of iron in the body by measuring several substances in the blood. These tests are often requested at the same time and the results considered together to help diagnose and/or monitor iron deficiency or iron overload.
Iron overload may be acute or chronic. Acute iron poisoning may occur, especially in children, with the ingestion of iron tablets. Chronic overload may be due to excessive intake, hereditary haemochromatosis, multiple blood transfusions or several other conditions.
How is the sample collected for testing?
A blood sample is taken by needle from a vein in your arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
Your doctor may request that you fast for 12 hours prior to some iron blood tests. In this case, only water is permitted.
Ask a Laboratory Scientist
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.