A healthcare professional is reviewing the laboratory results for a client who has a prescription for filgrastim. The healthcare professional should recognize that an increase in which of the following values indicates a therapeutic effect of this medication?

Filgrastim is a medication used to stimulate the production of neutrophils in patients with neutropenia. Neutrophils are a type of white blood cell that plays a crucial role in fighting off infections. Therefore, an increase in neutrophil count would indicate a therapeutic effect of filgrastim. The other options, such as erythrocyte count (red blood cells), lymphocyte count, and thrombocyte count (platelets), are not directly affected by filgrastim and would not indicate a therapeutic effect of this medication.