Differential diagnosis of anaemias

1. Big picture

Anaemia is not a final diagnosis; it is a clinical sign that the blood has reduced oxygen-carrying capacity, usually due to reduced haemoglobin. The examiner wants you to answer anaemia with a diagnostic algorithm, not with a random list.

The safest oral-exam approach:

Confirm anaemia
→ assess severity and urgency
→ look at MCV
→ look at reticulocyte response
→ check iron/B12/folate/hemolysis markers
→ search for blood loss, inflammation, kidney disease, marrow disease, or hemolysis
→ treat cause, not only haemoglobin

The hematology textbook defines anaemia by low haemoglobin and emphasizes that it is always a symptom, not a diagnosis; the underlying cause must be investigated. It also gives local lower limits: approximately Hb <130 g/L in men and <115 g/L in women.

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