<prompt> The earliest hematologic manifestation of megaloblastic anemia isIncrease in MCVHypersegmented polymorphsThrombocytopeniaLeukopenia  <response>: Microcytic anemiaMacrocytic anemiaSideroblastic anemiaIron deficiency anemiaThalassemiaAnemia of chronic disease Liver disease Hypothyroidism Folic acid vitamin B12 deficiency Cytotoxic drugs Megaloblastic anemiaTriad - Oval macrocyte , Howel Jolly bodies , Hypersegmented neutrophilsBone marrow - hypercellular bone marrow with megaloblast along with the presence of abnormal granulocytic precursors giant metamyelocyte band forms and large megakaryocytes with bizarre multilobate nuclei Peripheral smear - pancytopenia with presence of macrocyte MCV100 fl lacking central pallor ; large hypersegmented neutrophils 5 lobes Refer: Robbins Cotrans - Pathologic Basis of Disease, SAE, 1st edition, Vol I-pg no: 643-648 