[Normocytic anaemia due to multiple causes].

Anaemia can be subdivided into microcytic, normocytic and macrocytic categories, which give direction to the investigation to identify the cause of the anaemia. However, this is not always straightforward, as this case illustrates. A 73-year-old man with normocytic anaemia appeared to have both beta thalassemia trait (microcytic) and myelodysplastic syndrome (usually macrocytic). This led to a mixture of red blood cells of different sizes and an average normal MCV. The manual differentiation of the blood smear was helpful to find the right diagnosis.