Blood-tests Explained


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This website is intended to assist with patient education and should not be used as a diagnostic, treatment or prescription service, forum or platform. Always consult your own healthcare practitioner for a more personalised and detailed opinion

Iron Tests


At a Glance

Why Get Tested?

To evaluate your body's current level of iron

When to Get Tested?

When your doctor suspects that you may have too little or too much iron in your system

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

Your doctor may request that you fast for 12 hours prior to some iron tests; in this case, only water is permitted.

The Test Sample

What is being tested?

Iron is an essential nutrient to maintain life.It is needed in small quantities to help form normal red blood cells (RBCs) and is a critical part of hemoglobin, the protein in RBCs that binds oxygen in the lungs and releases it as blood circulates to other parts of the body.

Iron tests are ordered to evaluate the amount of iron in the body by measuring several substances in the blood. These tests are often ordered at the same time, where together, the results are considered in establishing the diagnosis and/or monitoring iron deficiency or iron overload.

  • Serum iron measures the level of iron in the liquid portion of the blood.
  • TIBC (total iron-binding capacity) measures all of the proteins in the blood that are available to bind with iron, including transferrin.
  • UIBC (unsaturated iron-binding capacity) measures the portion of transferrin that has not yet been saturated. UIBC also reflects transferrin levels.
  • Transferrin saturation is a calculation that reflects the percentage of transferrin that is saturated with iron.
  • Serum ferritin reflects the amount of stored iron in the body.

Low iron levels can lead to anemia, causing decreased production of RBCs that are microcytic and hypochromic. Conversely, large quantities of iron can be toxic to the body. This occurs when too much iron is absorbed over time, leading to the accumulation of iron compounds in tissues, particularly the liver, heart, and pancreas.

Iron is normally absorbed from food and transported throughout the body by binding to transferrin, a protein produced by the liver.About 70% of the iron transported is incorporated into the production of red blood cell hemoglobin. The remainder is stored in the tissues as ferritin or hemosiderin, with additional small amounts used to produce other proteins such as myoglobin and some enzymes.

Iron deficiency may be seen with insufficient intake, inadequate absorption, or increased nutrient requirements as seen during pregnancy or with acute or chronic blood loss. Acute iron overload may often occur with excess ingestion of iron tablets, especially in children.Chronic iron overload may be due to excessive iron intake, hereditary hemochromatosis, multiple blood transfusions, and a few other conditions.

How is the sample collected for testing?

A blood sample is drawn by needle from a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

Fasting for 12 hours before sample collection may be required. In this case, only water is permitted.

The Test