A complete evaluation of neutrophil function including: chemotaxis; adhesion; aggregation; phagocytosis; granule content and degranulation; respiratory burst activity; and bacterial killing; is expensive and requires the services of a specialized laboratory. However, preliminary screening of a patient with a predisposition toward infection, can be carried out using simple and inexpensive methods. These include examination of blood films, which may prove helpful in the diagnosis of Chediak-Higashi syndrome and specific granule deficiency; the Rebuck skin window test, which estimates chemotactic defects; the NBT test, which screens for chronic granulomatous disease patients; and peroxidase staining of the blood film in order to estimate the content of myeloperoxidase, when myeloperoxidase deficiency is suspected. For final diagnosis and determination of genetic transmission and radical treatment, ie, bone marrow transplantation, specific tests are indicated. Neutrophil function studies have also proved useful in detecting diseases in which defects in neutrophil function are secondary to the primary disorder. Indeed, increased neutrophil chemotaxis has been reported in the active phase of diseases such as: familial Mediterranean fever; psoriasis vulgaris, Behcet's syndrome and Sweet's syndrome. In these disorders the neutrophil chemotaxis assay has aided in the diagnosis and follow-up, particularly in evaluating the response to antiinflammatory agents, such as colchicine.