Iron Studies Interpretation | A4 Medicine  
                     Iron Studies
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A chart to aid in the interpretation of iron studies. These are set of blood tests which may  
include ferritin, serum iron, transferrin, transferrin saturation and TIBC.
Serum iron
Means ferric ions Fe3+ bound to serum transferrin Only 0.1 % of total body iron is bound  
to transferrin at any one time Little value if tested on its own as levels may fluctuate  
through the day. Serum iron would be decreased in Genuine iron deficiency Inadequate  
Fe absorption Chronic blood loss Pregnancy 3 rd trimester Chronic illnesses like SLE , 
Rh  arthritis.
Serum iron increased in – Haemolysis Iron overdose Lead toxicity Hepatic necrosis  
Haemochromatosis
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Transferrin
Major iron binding protein – carries iron from the liver to the bone marrow A beta  
globulin which is also an acute phase protein Synthesized in liver and regulates iron  
absorption Transferrin increases in iron deficiency to maximise the utilsation of available  
iron Also known as siderophilin
Transferrin reduced in chronic infections microcytic anaemia as a result of chronic  
diseases protein deficiency liver damage haemochromatosis kidney injury – loss of  
transferrin in urine malignancy atransferrinemia – genetic mutation
Transferrin elevated in Iron deficiency anaemia Pregnancy
Transferrin saturation
Percentage of transferrin and other iron binding proteins Helps find the cause of  
abnormal iron and TIBC levels Typically transferrin is 30 % saturated with iron  
Transferrin saturation rises in iron overload and falls in iron deficiency A rise in serum  
iron due to dietary iron intake can cause raised transferrin saturation. Transferrin  
saturation reduced in Iron deficiency anaemia Anaemia of chronic disease Acute phase  
response.
Transferrin saturation elevated in haemolytic anaemia sideroblastic anaemia  
megaloblastic anaemia patient with iron overload or iron intoxication Haemochromatosis
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Total iron binding capacity (TIBG)
Indicates the availability of iron binding sites on transferrin It is an indirect measure of  
transferrin concentration It is the sum of all the protein bound to iron TIBC would be  
elevated in 70 % of of patients with Fe deficiency anaemia. It is reduced in  
Haemochromatosis Hypoproteinaemia in malabsorption Burns Cirrhosis Renal disease  
Thalassemia Hyperthyroidism Non-iron deficiency anaemia.
TIBC elevated in Pregnancy Iron deficiency Acute hepatitis Acute and chronic blood loss.  
Isolated elevated transferrin saturation- repeat a fasting sample. If consistently raised  
consider HF E  gene analysis with pre-test counseling
Acute hepatic injury can present as raised iron , transferrin ,transferrin saturation and  
ferritin . This is due to leakage of hepatic content and can be easily confused with iron  
overload
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References
1.Interpreting iron studies BMJ 2017;357:j2513 ( 2017 , June 15)
2.Melbourne haematology A guide to the interpretation of iron studies – Overview
3.Deranged Physiology Interpretation of iron studies via 
www.derangedphysiology.com
4.O gun AS, Adeyinka A. Biochemistry, Transferrin. [U pdated 2019 Jan 16]. 
In:  StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019
5.TIBC , Transferrin and Transferrin saturation from www.labpedia.net
6. www.Irondisorders.org- How do I know if I am anaemic
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