Clinical value of in vitro diagnostic in asthma

The better comprehension of the dynamics involved in the etiopathogenesis of asthma in determined circumstances needs the complement of immunologic methods. The improved immunologic methods for the diagnosis of allergic diseases in the last twenty years has in general confirmed the results obtained by the intradermal test. However, it is important to bear in mind that in a reliable "in vivo" diagnostic, the technique has to be considered, and that there is a better correlation in the intracutaneous test than in the Prick one. Of the various immunologic tests carried out, the hemagglutination test offers a better reliability in the diagnosis of food-induced bronchial asthma, together with the histamine release test. In our experience, the RAST was less reliable when it came to the diagnosis of food allergy, though on the other hand it was applicable for inhalant allergens (pollens and dermatophagoides). In clinical practice and in daily routine work ups, all these techniques of course, impose an additional cost for diagnosis. Therefore, the use of sophisticated modern immunologic methods has to be reserved unless needed for clinical research, or as happens in some cases, for suspicious clinical histories with negative skin tests, in order to confirm the possible allergens responsible.