According to the definition in textbooks such as Dacie and Lewis' Practical Haematology, neutrophil hyper-segmentation is defined as the presence of neutrophils with six or more nuclear lobes or the presence of more than 3% of neutrophils with at least five nuclear lobes. This important laboratory finding can be observed in various clinical conditions including megaloblastic anaemias (an important diagnostic feature), chronic infections, myelodysplastic syndromes, myeloproliferative disorders, etc.

In this series of images, we see neutrophil hyper-segmentation in the patient. The patient is a 54-year-old woman with a recent infection. Other CBC parameters were normal and were as follows:

WBC: 7.9*10³/μL

Neu: 80%

Lym: 15%

Mon: 4%

Eos: 1%

Baso: 1%

RBC: 3.92*10⁶/μL

Hb: 12.3 g/dL

HCT: 36.5%

MCV: 93 fL

RDW-CV: 12.6%

PLT: 256*10³/μL