Skin prick testing with standardized extracts from 3 different manufacturers. A comparative randomized study.

The aim of this study was to compare skin reactivity to routine allergen prick test with panels of allergens, supplied by three different manufacturers. The allergens comprised ten aero-allergens commonly used for skin prick test in Northern Europe, and included pollen, dander, house dust mites, and moulds. Two hundred consecutive patients were tested. The methods for standardization of allergen extracts, declaration of allergenic potency, and recommended lancets differed. The equipment were Soluprick SQ (Allergologisk Laboratorium A/S, Denmark) (ALK), Alphatest (Dome/Hollister-Stier, U.K.) (DHS), and Phazet (Pharmacia, Sweden) (PHA). The coefficient of variation for the allergen coated PHA (same lancet was applied twice) was 0.31, and for ALK and DHS allergen extracts 0.13 and 0.18, respectively. The frequencies of patients with positive reactions to the various allergens were generally similar, although DHS appeared to elicit less positive reactions to Timothy, dog, and Dermatophagoides pteronnyssinus. For the individual physician, it may be important to know the allergenic activity of the different allergens in his routine panel compared to the activity in other similar panels.