Culled from human plasma, intravenous immunoglobulin (IVIG) is an expensive and limited resource. These constraints underscore the importance of ensuring that our clinical uses of IVIG are in line with the applications for which we have best demonstrated its efficacy. Yet IVIG has only amassed a short list of FDA-approved indications, and is often employed as an off-label therapy. In what areas is our use of IVIG best supported by the literature, and is this consistent with how the agent is most commonly used? Host Dr. Charles Turck examines these questions and more with Dr. Michael Gabay, clinical assistant professor at the University of Illinois at Chicago College of Pharmacy, where he directs the university's Drug Information Group and Prior Authorization Services.