Differential white blood cell count - Percentages of the different types of white blood cells. There are five main types of white blood cells: neutrophils (also called granulocytes - GR and GR# in the table below), lymphocytes, monocytes, eosinophils, and basophils.Neutrophils, also called granulocytes because they contain enzyme-filled granules, are the most prevalent white blood cell type. They help protect the body against bacterial and fungal infections and ingest foreign debris. They consist of two types: band (immature) and segmented (mature) neutrophils.

Oncologists pay particular attention to the absolute neutrophil count (ANC)(which is also called the absolute granulocyte count or AGC or GR# as many of the cytotoxic chemotherapy drugs decrease the ANC, making patients more susceptible to infections. Most chemotherapy regimens require an absolute neutrophils count (GR and GR# in the table below) to be ≥ 1500 cells/μL.