Hypersegmentation of neutrophils is defined as presence of 5% or more neutrophils with five or more lobes or single neutrophil with 6 lobes. It is an important haematological feature observed in cases of cobalamin or folate deficiency.  In this study, we evaluated the presence of neutrophil hypersegmentation in all peripheral smears received in our hematology laboratory.

We included 150 samples which had peripheral smear findings of neutrophil hypersegmentation but without evidence of macrocytosis.  Complete blood counts were obtained using automated haematology analyzers and peripheral smear study correlated with these counts.  Peripheral smears were stained using Leishman Stain and observations documented. Hypersegmentation was found more commonly in men with normocytic normochromic RBC indices.  Neutrophilia is the most commonest association with hypersegmentation. 

Our study shows that neutrophil hypersegmentation is not specific for Vitamin B12/Folate deficiency anemias and are frequently observed in iron deficiency anemia.  But, in the cases of iron deficiency anemia with neutrophil hypersegmentation co–existing folate/Vitamin B12 deficiency has to be ruled out.