Clinical ambiguities--ongoing questions.

Many factors need to be considered when choosing the mode of delivery of immunoglobulin (IgG) replacement therapy for a given patient with primary immunodeficiency disease (PIDD). Despite some general guidance as provided in the previous discussions, a number of ongoing questions remain. This article attempts to provide some answers and clarification for clinical situations in which the choice of intravenous IgG (IVIG) or subcutaneous IgG (SCIG) may be ambiguous.