Primary immunodeficiency (PID) is a cluster of disorders that share a common theme of excessive susceptibility to infection and other associated clinical problems. These serious episodes of infection markedly impair the patients' ability to lead a normal life. While individual diseases are rare, PID as an entity is not uncommon. To date, there are more than 160 genetically distinct PID diseases, affecting more than 10 million children and adults worldwide (Pommerville, 2006). As appropriately stated, PID is common enough that a primary care physician is likely to encounter several patients in their practice. Wood et al. indicated that ...