This article is for Medical Students & Professionals
This is a Question & Answer revision article designed for medical students and professionals preparing for the PLAB, MRCP or USMLE examinations. They are based on actual questions from these examinations. You may find the What Is Blood? article more useful, or one of our many articles on Diseases & Conditions, Medical Syndromes, Health & Wellness or Home Remedies.
Application of iron studies
MCQ: clinical scenario
MCQ: answer
MCQ: explanation
Application of iron studies
The assessment of iron deficiency or overload may be complicated by the presence of an acute phase response or hepatocellular disease. In general, serum ferritin is the preferred test for the assessment of iron deficiency, however levels may be normal (up to 100 µg/L) when iron deficiency coexists with an acute phase response. Soluble transferrin receptor levels are not affected in an acute phase response; levels are normal in anaemia of chronic disease uncomplicated by iron deficiency. An alternative approach to the patient with suspected iron deficiency and/or chronic inflammatory disease is to assess the haemoglobin response to iron therapy.MCQ: clinical scenario
Consider the following values.MCV: Decreased; Serum ferritin: Increased; Total iron binding capacity: Normal; Serum iron: Increased; Marrow iron: Present.
The most likely diagnosis is:
a) Thalassaemia trait
b) Hypoparathyroidism
c) Hereditary sideroblastic anaemia
d) Anaemia of chronic disease
e) Iron deficiency anaemia
MCQ: answer
The correct answer is CMCQ: explanation
Patients with a defect in mitochondrial function resulting in a sideroblastic anaemia can also present with a microcytic, hypochromic anaemia. Hereditary sideroblastic anaemia is a rare condition that presents in childhood either as an X-linked or autosomally inherited condition. Red blood cell morphology is typically dimorphic, and measurements of iron supply make the distinction from iron deficiency quite easy. Patients who develop an acquired ringed sideroblastic anaemia typically exhibit excessive iron accumulation, even to the point of tissue iron overload. Their red blood cell morphology can be quite variable, while marrow morphology demonstrates the pathognomonic finding of ringed sideroblasts.Iron deficiency | Anaemia of chronic disease | Iron deficiency and inflammation | Acute phase response | Iron overload | |
---|---|---|---|---|---|
Serum iron | Decreased | Decreased | Decreased | Decreased | Increased |
Serum transferrin, Total iron binding capacity (TIBC) | Increased | Decreased | Decreased (low normal) | Decreased | Decreased or normal |
Transferrin saturation | Decreased | Decreased | Normal or decreased | Decreased | Increased |
Serum ferritin | Decreased | Normal (> 100 ug/l ) | “Normal” | Increased | Increased |
Soluble transferrin receptor | Increased | Normal | Increased | Normal | Decreased |
Also see the separate Q&A article, Interpreting Iron Studies.
Reference(s)
1). Royal College of Pathologists of Australasia (RCPA): Iron studies. Available online: https://www.rcpa.edu.au/Manuals/RCPA-Manual/Pathology-Tests/I/Iron-studies
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