Evaluation of the Phadiatop test in an epidemiological study

Sera from 204 adult patients with chronic airways obstruction were analysed with the Phadiatop, a new allergosorbent test with a paper disc containing the most relevant inhalant allergens, the PRIST for total IgE determinations, and a panel of seven RAST tests with the common inhalant allergens in The Netherlands as reference. The aim was to evaluate the Phadiatop as screening test in the in vitro diagnostic procedures in an epidemiological setting. The Phadiatop was classified positive or negative according to percentage binding, total IgE was considered elevated at values greater than 100 kU/l and the RAST panel positive when at least one RAST result was class greater than 1. The prevalence of inhalant atopy came to 27.9%. The predictive value of the Phadiatop for a positive RAST panel was 96.4%, and for a negative RAST panel 97.3%. For the PRIST these values were 51.9% and 87.2% respectively. The correlation between the log percentages binding of the Phadiatop and the RAST panel was 0.93. It is concluded that the Phadiatop is a valuable test for the screening of inhalant atopy, and as the percentage binding of the Phadiatop may reflect the degree of sensitization it could also be applied as a quantitative measure especially for epidemiological purposes.