[Biological assays in allergology: constraints, concepts, criteria, and methods of evaluation]

The in vitro diagnosis of allergies is submitted to several constraints some shared by all the in vitro methods and some which are specific of immuno-allergology. The in vitro diagnosis of allergies involves various parameters among which the allergen by itself is far the most complex. On the basis of a studied population having an optimal size, the most powerful statistical parameters are the positive predictive value, the negative predictive value and the efficiency. The bio-clinical correlations lead to the involvement of another parameter which is the prevalence of the clinical reaction which may be corrected by a clear clinical history. Finally, the absence of absolute gold standard in allergology lead to the conclusion that allergy diagnosis is still based on the synthesis of various clinical and biological arguments.