The use of Phadiatop® in mass‐screening programmes of inhalant allergies: advantages and limitations

Abstract
Summary: The validity of Phadiatop® as a tool in the mass screening for inhalant allergies was investigated. Seventy‐nine out of 600 recruits (13.2%) were classified as allergic to inhalant allergens (68 oculorhinitis; 11 asthma) on the basis of positive history, confirmed by skin testing and/or RAST for the seven most common aero‐allergens in Italy. Another 74 subjects had positive RAST and/or skin tests, yet had never experienced allergic symptoms. Phadiatop was positive in 145/600: in 78 out of 79 allergies and in 67 RAST‐positive non‐allergies. Correlation between Phadiatop and RAST was statistically significant, though higher for grass pollens (r= 0.85, P < 0.001) than for Dermatophagoides pteronyssinus (r= 0.68, P < 0.01). PRIST (cut‐off 220IU/ml) identified 36/79 allergies (45.6% sensitivity, whereas that of Phadiatop was 98.7%). As the high percentage of cases in the unselected population had specific serum IgE against inhalant allergens and no allergic symptomatology, the Phadialop‐positive predictive value falls to 53.7%, thus creating the need for Phadiatop‐positive subjects to undergo further investigation for an appropriate diagnosis. Given this limitation, Phadiatop appears to be an important step forward in the field of mass‐screening programmes for inhalant allergies.