Our laboratory at Meir Medical Center, Kfar Saba, is the country's main center for neutrophil function, and serves about 80% of Israel's population. Patients are referred subsequent to recurrent, persistent, or unusual infections and after completing preliminary screening of the immune system and ruling out a humoral, cellular or complement immune deficiency. Initial workup includes chemotaxis, superoxide production (SOP), and bactericidal activity (BA). Based on test findings, further evaluation for a qualitative phagocytic disorder is conducted. Overall, impairment of phagocytic activity is found in about 33% (impaired chemotaxis in 16%, SOP in 6%, and BA in 24%). In the other 67%, no impairment of the immune function is found that can explain their tendency for recurrent pyogenic infections.