Diagnostic methods in allergy

In the diagnosis of allergic diseases a variety of in vivo as well as in vitro methods are clinically used. In vivo methods comprise different kinds of skin tests (epidermal, scratch, prick, intradermal), passive transfer tests (passive cutaneous anaphylaxis in monkeys) as well as provocation tests in various organs (conjunctival, nasal, bronchial or oral challenge). Skin tests are the most simple and most widely used diagnostic approaches in allergy. They are, however, not completely without risk, especially when dealing with drug allergy. Provocation tests are even of greater risk and unpleasant for the patient. It is, therefore, to be regarded as a real progress in allergy diagnosis that several in vitro techniques are available quantitating IgE-mediated reactions. Among these in vitro tests both radio-immunoassays (RIA) - e.g. the radio-allergo-sorbent test (RAST) - as well as enzyme-immuno-assays (EIA) are available. In vitro histamine release from peripheral leucocytes or basophil degranulation tests together with lymphocyte transformation studies enrich the presently available spectrum of in vitro allergy diagnostics.