22nd May 2023

Microcytic anaemia

Microcytosis is defined as an MCV<80fL, and when associated with anaemia is termed microcytic anaemia.

Causes of microcytic anaemia include:

• Iron deficiency
• Anaemia of chronic disease
• Thalassaemia
• Sideroblastic anaemia – results from impaired incorporation of iron into haemoglobin molecules. This can be congenital or secondary to alcohol excess, drugs (isoniazid, chloramphenicol), or myelodysplasias. The MCV is low or normal in congenital forms but can sometimes be raised in acquired forms.
• Lead poisoning