Agranulocytosis is a very serious side-effect of treatment with clozapine. For this reason, the Dutch guidelines state the specific values of leukocyt and neutrophil counts at which treatment with clozapine should be discontinued. We focus on a patient with a benign ethnic neutropenia who, despite a low neutrophil count, was allowed to continue taking clozapine. We discuss a number of important practical considerations that can affect the way in which leukocyte and neutrophil counts are interpreted in relation to the use of clozapine.