Anaemia — Investigation Approach

Haematology

Hb below age/sex norm (M <130, F <120 g/L) reducing oxygen-carrying capacity.

Causes

  • Microcytic: Fe deficiency, thalassaemia, sideroblastic, anaemia of chronic disease (late)
  • Normocytic: ACD, CKD, mixed, haemolysis, acute blood loss
  • Macrocytic: B12/folate, alcohol, hypothyroidism, MDS, drugs

Investigations

  • FBC, MCV, reticulocytes
  • Iron studies, B12, folate
  • U&E, LFT, TFT, CRP
  • Haemolysis screen (LDH, haptoglobin, bilirubin, blood film, DAT)
  • Endoscopy if Fe-deficient and no obvious cause

Management

  • Treat cause
  • Oral ferrous fumarate 200 mg OD–TDS or IV iron
  • B12/folate replacement (B12 first to avoid subacute combined degeneration)
  • Transfusion only if symptomatic / Hb <70

Clinical pearls

  • Iron deficiency in male / post-menopausal female → consider GI malignancy
  • Pernicious anaemia: anti-IF antibodies, lifelong IM B12

Educational — verify locally.

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