Evaluation and clinical interpretation of hypergammaglobulinemia E: differentiating atopy from immunodeficiency.

Increases in total serum IgE levels can be observed in many diverse conditions, from infection to atopy to primary immunodeficiency. The differentiation of atopy from immunodeficiency most often is made on a clinical basis, after taking findings from history, physical examination, and laboratory studies into consideration. However, total IgE level is neither a sensitive nor a specific diagnostic marker for any particular disease and, therefore, should not be relied on to establish a diagnosis of either atopy or primary immunodeficiency.