Leukocytosis and Tobacco Use: An Observational Study of Asymptomatic Leukocytosis.

Purpose: This study aimed to characterize the white blood cell differential of tobacco smoking-induced leukocytosis and describe the longitudinal impact of smoking cessation on this peripheral blood abnormality.

Methods: Medical records of patients undergoing evaluation by hematologists for persistent leukocytosis were reviewed. Patients in whom leukocytosis was determined to be secondary to tobacco use after exclusion of other causes were identified.