The 'Phadiatop Paediatric': a useful in-vitro test on an atopic immune response in infants and young children

The aim of this study was to evaluate a new test for IgE antibody screening in children--the Phadiatop Paediatric. The mixture of allergens in this test contains the food and inhalant allergens for infants and children most relevant. 180 sera were selected from samples submitted for routine diagnostic IgE antibody assay. 91% of these sera were from children less than 5 year old. Half the sera were positive in RASTs that were initially requested by the physicians and the highest RAST scores for each serum were equally distributed over the range RAST class 1-4. 20 control sera were from children 1-4 years old. Results of the Phadiatop Paediatric were compared with results of the combination 'Phadiatop + mixed-food-RAST'. 22% of the sera that were negative in all RASTs that were initially requested by the physicians were positive in both tests. This suggests that an IgE antibody response to food components or inhalants was underdiagnosed in these cases. Whereas 135 sera were found positive in the Phadiatop Paediatric, only 116 sera had a positive Phadiatop result and/or a result of the mixed-food-RAST that was RAST class 1 (greater than or equal to 0.35 PRU/ml) or higher. In 11 of 16 sera with RAST class 0/1 (0.18-0.35 PRU/ml) in the mixed-food-RAST specific IgE against individual food allergens with RAST class 1 or higher could be demonstrated. Results of Phadiatop and Phadiatop Paediatric were not only expressed as 'positive' or 'negative', but also as a serum:reference ratio. Clinical documentation was collected retrospectively from the written case reports of 171 children.(ABSTRACT TRUNCATED AT 250 WORDS)