A routine blood test can be done first to see if there is anemia, usually megaloblastic anemia is manifested as macrocytic anemia, and a bone marrow test can be done to find out if the red blood cells are obviously megaloblastic. In addition, a bone marrow smear can be used to examine the bone marrow, which is generally active or markedly active, with significant megaloblastic proliferation in the red lineage and megaloblastic proliferation in the granulocyte lineage, with many lobulated mature granulocytes.