<prompt> The earliest manifestation of megaloblastic anemia isMacrocytosisHypersegmented neutrophilsBasophilic stipplingCabot ring  <response>: Peripheral blood pictureBone marrow picture1.Macrocytosis MCV, MCH. Normal MCHC2.Peripheral smearMacroovalocytes Few nucleated RBCsEvidence of dyserythropoiesis like--Basophilic stippling-Cabot ring-Howell- Jolly bodies3. Hb4. Hematocrit 5.Reticulocyte count - Normal or mild decrease6.White cells- Leucopenia7.Hypersegmented neutrophils Macropolycytes- First manifestation 8. Platelets9.Pancytopenia 10-20Lab investigations:10.Serum iron, ferritin - in pure VitB12 Folate defect11.Serum bilirubin LDH - due to hemolytic component12.Schillings test: Used to assess status of intrinsic factor IF Vit B12 to distinguish pernicious anemia from other causes of Vit.B12 deficiency.1.Moderate- marked hypercellularity2.Erythroid hyperplasia3.M:E ratio reversal4.Ehropoiesis- Megaloblastic5.Giant metamyelocytes6.Mildly reduced megakaryocytes7.BM iron moderately increased in pure Vit B12 Folate defects.Ref: Harrison 18e p866, 17e p645-646, Tejinder Singh 2e p54-61 