[Phadiatop-Paediatric, a new screening test for atopy: a comparison with RAST results]

The results obtained using a new in vitro screening test for atopy Phadiatop-paediatric (Phad-P) and RAST for multiple food and inhalant allergens in 132 children (82 with atopic dermatitis and 50 with a negative history of atopic symptoms are compared. 64% of the subjects were RAST-positive for food allergens (55/82) in those with dermatitis and only 5/50 in those without atopic symptoms. The only difference between the new test and the RAST is that a mixture of food and inhalant allergens, rather than a single allergen, is conjugated to the paper disk and the results are expressed as positive or negative so as to identify atopic subjects for further allergologic evaluation. The sensibility and specificity of Phad-P as compared to RAST were respectively 87% and 85% with an efficiency of 86%. On the basis of these data, assuming a 20% prevalence of atopy, in the general population the predictive value of negative results of the new test would be 97% and of positive results 59% with an expected efficiency of 86% values similar to those observed in other studies and at the moment considered satisfactory for a screening test fo atopy.