Classification of neutrophils with differing nuclear lobes. Percentages in normal blood smear 1 lobe, 5%; 2 lobes, 35%; 3 lobes, 41%; 4 lobes, 17%; 5 lobes, 2%. ÒShift to leftÓ involves higher percentage of 1-lobed nuclei and usu. represents bacterial infection. ÒShift to rightÓ involves higher percentage of multilobed nuclear and indicates folic acid or vitamin B12 deficiency.