Ferritin and Iron Deficiency Quiz

Ferritin and Haemosiderin

• Ferritin is the main iron storage protein found in bone marrow, liver, and spleen.
• It's made of apoferritin and iron-phosphate-hydroxide (ferrihydrite)
• Apoferritin has catalytic activity, oxidizing Fe²⁺ to Fe³⁺.
• Ferritin is a water-soluble, hollow sphere with 24 subunits.
• Up to 4500 iron atoms can be stored in a single ferritin molecule.
• 1 µg/L of serum ferritin corresponds to about 8 mg of stored iron.
• Iron is incorporated into the ferritin core as Fe³⁺ through pores in the protein.

Iron Deficiency Diagnosis

• A low ferritin level is strong evidence of iron deficiency.
• Ferritin is an indicator of accessible iron stores.
• Borderline ferritin levels should be assessed alongside C-reactive protein (CRP).
• Iron deficiency is suggested by ferritin levels <12 µg/L in children under 5 and <15 µg/L in those over 5 years old.
• Ferritin levels increase in inflammatory states (e.g., kidney disease, liver disease, malignancy), making it an acute-phase reactant.
• UK guidelines suggest investigating iron deficiency with levels below 150 µg/L.

Haemosiderin

• Haemosiderin is an insoluble iron-protein aggregate.
• Haemosiderin acts as long-term iron storage, unlike ferritin.
• It's not easily mobilized.
• When stained with Prussian blue, haemosiderin appears blue.
• Haemosiderin is examined in bone marrow, liver biopsies, or urine samples when intravascular haemolysis is suspected.
• It's useful for evaluating iron overload and identifying ring sideroblasts.
• Ferric iron + potassium ferrocyanide → ferric ferrocyanide (Prussian blue)

Microscopic Analysis (Perl's Stain)

• Perl's stain is used to visualize iron stores in tissues.
• Microscopic images stained with Perl's stain can show increased iron stores in iron overload conditions.

Recommended Tests for Iron Deficiency

• Full blood count with red blood cell parameters, serum ferritin, C-reactive protein (CRP) are the initial tests to check for iron deficiency.
• If acute/chronic inflammation is present or CRP is elevated, further tests may be needed.
• In cases with ferritin <15 µg/L, the suspicion of iron deficiency is high and further investigation is required.

Test your knowledge on ferritin as an iron storage protein and its role in diagnosing iron deficiency. This quiz covers its structure, function, and the clinical implications of ferritin levels in different age groups. Understand how ferritin levels can indicate iron stores amidst various health conditions.