Total IgE influences the relationship between skin test and RAST.

Positive correlations were found between total IgE, skin prick test (SPT) and RAST results with tree pollen allergens. The relationship between SPT and RAST was influenced by the level of total IgE. At each level of atopy, defined according to the strength of SPT, patients with high total IgE had higher RAST values than patients with low total IgE.