Megaloblastic pancytopenia vis-a-vis non-megaloblastic pancytopenia: is mean platelet volume useful discriminating indicator

Introduction: Megaloblastic anaemia may present with pancytopenia and clinically mimic other causes of pancytopenia including myelodysplastic syndrome or aplastic anaemia. Bone marrow examination may be required for precise differentiation. The study was conducted to evaluate the role of mean platelet volume (MPV) to discriminate between pancytopenia due to megaloblastic anaemia or non-megaloblastic causes. Methods: A total of 268 cases of pancytopenia were divided into megaloblastic and non-megaloblastic group depending on clinical, laboratory and bone marrow examination. Mean MPV was statistically analyzed in both the groups along with comparison with healthy controls. Results: The mean MPV in 88 cases of megaloblastic group (7.97 fl) was although statistically significantly higher than mean MPV in 180 cases of non-megaloblastic group (7.04 fl) with P value <0.05 but had limited sensitivity and specificity to discriminate megaloblastic and non-megaloblastic pancytopenia (cut off of 7.45 fl was 63.6% sensitive and 67.3% specific as observed by receptor operating characteristic curve analysis). The mean MPV in aplastic/hypocellular marrow and acute leukaemia category of non-megaloblastic group was significantly lower than megaloblastic group of pancytopenia (P value <0.05). MPV was also significantly lower in non-megaloblastic pancytopenia as compared to controls (P < 0.001) while there was no statistical difference in MPV between megaloblastic pancytopenia and controls (P < 0.057). Conclusion: MPV has limited sensitivity and specificity to discriminate between megaloblastic and non-megaloblastic pancytopenia. Pancytopenia due to aplastic/hypocellular marrow and acute leukaemia has significantly lower MPV than megaloblastic group while other pancytopenic cases do not show any statistical difference in MPV from megaloblastic pancytopenia.