ABSTRACT
Megaloblastic anaemia and aplastic anaemia are important causes of pancytopenia in India. Since both may have presence of macrocytes, peripheral smear examination alone may pose a difficulty in distinction between the two in the absence of macro-ovalocytes and hypersegmented neutrophils. The present study was conducted to evaluate the role of red cell indices in differentiation between macrocytosis of aplastic anaemia and megaloblastic anaemia. Haemogram from 25 cases each of biopsy proven megaloblastic anaemia and aplastic anaemia were reviewed. It was observed that MCV was greater than 97 fl in 15 cases of aplastic anemia (mean MCV 109.7 fl), and 25 cases of megaloblastic anaemia (mean MCV 113.2 fl). Hb, MCV & MCHC were comparable in the two groups. However, mean RDW in megaloblastic anaemia (mean 87.7 fl) was significantly higher than those in aplastic anaemia (mean 71.4 fl). The difference in RDW of patients with megaloblastic anaemia and aplastic anaemia was statistically significant. We conclude that RDW can be of help to differentiate between the two conditions.