Leukopenia refers to a low white blood count (WBC) that may be due to lymphopenia as well as neutropenia, while granulocytopenia refers to a reduced number of granulocytes (neutrophils, eosinophils, and basophils). * Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1500/µL.
ANC  =  WBC (cells/µL)  x  percent (PMNs  +  bands)  ÷  100.
Neutrophilic metamyelocytes and younger forms are not included in this calculation.
The risk of infection begins to increase at an ANC below 1000/µL.<unk>  refers to severe neutropenia (ie, ANC less than 500/µL).<unk><unk>  neutropenia or<unk>  occurs as an idiosyncratic reaction.
In research protocols, the definition excludes known cytotoxic agents or diseases that can cause neutropenia and requires that the offending<unk>  be administered within four weeks of the onset of neutropenia.
Neutrophilic metamyelocytes and younger forms are not included in this calculation.
Drug-induced agranulocytosis
Leukemoid reaction
Transient erythroblastopenia of childhood
Acute megakaryoblastic leukemia
T-cell prolymphocytic leukemia electrocardiogram
Prolymphocytic leukemia
Aleukemic leukemia
Acute myelomonocytic leukemia