Prick and intradermal tests compared with specific IgE in allergic assessment

Allergic assessment in symptomatic patients often requires more tests and they can be conflicting. Sixty outpatients, suffering from seasonal or periannal respiratory symptoms, underwent prick tests, intradermal reactions and specific IgE (IgEs) determination by enzime immunoassay for eight common allergens; in addition total IgE were measured. At the end of the study 512 tests were performed. Total serum IgE levels had no significance in the results. There was a statistically different behaviour among three methods; a positive or negative concordance was found in 64.1% of tests whereas in the others (35.9%) results were conflicting. In particular it was seen that a prick test positive was confirmed by intradermal reaction and a test prick and intradermal negative was not probably confirmed by IgEs. Serum specific IgE levels were higher in subjects prick and intradermal positive than in prick negative and intradermal or IgEs positive subjects. Intradermal reactions were found positive especially in mites and often they were not confirmed by prick or IgEs. So prick test is always the routine test; intradermal test ought to be used if there were prick tests negative and patient's history positive. If prick and intradermal test were found negative it is plausible that the measurement of specific IgE will be negative circumscribing even more the number of individuals where determination of serum specific antibody is necessary.