Curriculum · Hematology
The dimorphic blood film
What it is
A dimorphic film is one on which you see RBCs that are both microcytic and macrocytic. Two sizes sit side by side on the same film, and that is what the word dimorphic names. The film is read for the size and the shape of the red cells, and the dimorphic film is the one that shows two sizes at once.
Causes and risk
The differential diagnosis is short:
- IDA together with B12 or folic deficiency, so that each deficiency makes its own size of cell
- IDA on treatment, where the reticulocytes will appear as macrocytic