The contribution of a new method of measurement of total IgE by the Fluoro-Enzymo-Immuno-assay (FEIA) with the assistance of Pharmacia UNICAP automation is very reliable since, when compared with the measurement by the CAP SYSTEM RIA on 144 patients who were clinically allergic (84 with a raised and 60 with a normal IgE titre) the result of a comparative study between the two techniques is statistically highly significant. The two methods were also compared by age groups and these results were also statistically highly significant.