Quantitative skin prick tests and specific IgE (CAP System) for D. pteronissynus--correlation of results in a paediatric population.

The CAP System compared with RAST has a greater sensitivity, with the same specificity, as well as an excellent correlation with skin prick tests (SPT), as documented by others. Standardization of SPT is essential for routine and investigational purposes. We used a standardized lancet (DHS), and the methodology of reading the SPT was a computerized digitalized graphics tablet coupled to an IBM-PC AT using CAD software, expressing the result as wheal areas with cut off +/- at 7 mm2. The method is precise and reproducible with a mean coefficient of variation (cv) intratester--T1: 3.1%, T2: 3.5% and a cv intertester: 2.93%. We compare the results of SPT of two different allergen extracts for Dermatophagoides Pteronissynus (DPt) (Bencard; Merck/Allergo-Pharma, standardized in SBU) and correlate them with specific IgE, in 122 patients, 72 males and 50 females, aged 3 to 19 years. The results between the extracts and the results of specific IgE obtained by CAP System with each of the extracts, were correlated. 34 patients were considered to be non atopic. 88 patients showed at least one positive result with one test, being those used to correlate the positive results.... The results showed good correlations for quantitative SPT between Bencard and Merck/Allergo-Pharma, as well as for the capacity of eliciting positive results. When SPT were compared to specific IgE as +/- and as quantitative results, there were good correlation for Bencard/CAP and Merck/CAP. The results obtained suggest that CAP can be used to validate allergen extracts of DPt and that studies with other extract are advisable.