Ferritin, serum iron, TIBC and transferrin saturation help assess iron stores and iron availability. This tool explains common iron study patterns but cannot diagnose the cause.
Iron studies are blood tests used to assess the amount of iron in the body, how well iron is being transported and whether iron stores are adequate. They include ferritin, serum iron, TIBC and the calculated transferrin saturation.
Ferritin is a protein that stores iron inside the body. It is one of the most useful tests for assessing iron stores. Low ferritin often suggests reduced body iron reserves. However, ferritin is also an acute phase reactant — it can rise during inflammation, infection and some liver conditions, which means a normal or elevated ferritin does not always exclude iron deficiency.
Serum iron measures the amount of iron circulating in the bloodstream at the time of the blood test. It can fluctuate throughout the day and is affected by recent iron intake, supplements and illness. Serum iron is usually interpreted alongside ferritin, TIBC and transferrin saturation rather than in isolation.
TIBC (Total Iron Binding Capacity) estimates how much iron-carrying capacity is available in the blood. It reflects the level of transferrin, the main iron-transport protein. A high TIBC often suggests that the body has spare capacity to carry more iron — which is commonly seen in iron deficiency. A low TIBC may be seen during inflammation or chronic illness.
Transferrin saturation (TSAT) is calculated from serum iron and TIBC. It estimates how much of the body's iron transport capacity is currently occupied by iron. A low TSAT suggests reduced iron availability. A high TSAT may suggest that iron is present in excess.
Yes. Ferritin may rise during inflammation, infection and some liver conditions, potentially masking iron deficiency. In this situation, a normal or mildly elevated ferritin alongside a low serum iron and low TSAT may still suggest a functional iron deficiency. This is why the clinical context, CRP and symptoms are important when interpreting iron studies.
Medical review is important when symptoms are significant — such as fatigue, pallor, breathlessness or weakness — when haemoglobin is low, when iron studies are abnormal or when results do not fit the expected pattern. Do not start iron supplements without medical advice, as unnecessary iron can be harmful.
Common questions about iron studies results — answered by Sineth Hospitals.
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