Inasmuch as neutrophils are the primary cellular defense against bacterial and fungal infections, disorders that affect these white cells typically predispose individuals to severe and recurrent infections. Therefore, diagnosis of such disorders is an important first step in directing long-term treatment/care for the patient. Herein, we describe methods to identify chronic granulomatous disease (CGD), leukocyte adhesion deficiency (LAD), and neutropenia. The assays are relatively simple to perform, cost-effective, and can be performed with equipment available in most laboratories.