Reproducibility of Standardized Bronchial Allergen Provocation Test

Abstract

Standardized bronchial allergen provocation was performed twice (with an interval of median 14 days (range 14-44)) in 19 extrinsic, well-defined asthmatic patients to study the reproducibility of the bronchial response. Smoking and medications were strictly withheld prior to the provocation. Ten-fold increasing concentrations of allergen solution 0.9 ml were inhaled by tidal volume breathing for 5 min at 10-min intervals. The actual dose given was expressed by the concentration of the solution used. Forced expiratory volume in the first second (FEV1) was used to determine responses, and the provocation continued until an allergen concentration (allergen PC20) was reached which caused at least 20% decrease of the post-saline FEV1. All provocations were followed by a bronchial reaction within clinically acceptable limits. The reproducibility was high, evaluated by the Spearman rank correlation coefficient Rho = 0.90 (P less than 0.01). It is concluded that bronchial provocation with allergens performed as outlined in this study represents a reproducible test which can be applied in routine allergy diagnostics, and in further investigations concerning specific bronchial reactivity.

Late airway response increases at repeat allergen challenge

“…It is obvious that this procedure allows conclusions about changes in specific reactivity in the immediate phase to be drawn only from analysis of bronchial response in the subgroup of 11 patients (11). This purpose was achieved by choosing an appropriate interval between challenges and titration method for challenge, thereby making it possible to evaluate changes in the late response between the 2 days.…”

“…This purpose was achieved by choosing an appropriate interval between challenges and titration method for challenge, thereby making it possible to evaluate changes in the late response between the 2 days. It is obvious that this procedure allows conclusions about changes in specific reactivity in the immediate phase to be drawn only from analysis of bronchial response in the subgroup of 11 patients (11).…”

Reproducibility of responsiveness to a standardized bronchial allergen provocation—Rt compared to FEV1 as measurement of response to provocation

“…A bronchial allergen provocation seems to be an important supplement in the diagnostic arsenal to confirm the presence of extrinsic asthma. Determination of the immediate bronchial response to inhaled allergens has been shown to be highly reproducible when measured by the forced expiratory time volume curve (first sec expiratory volume (FEV,)) [3,4] but the responses may also be determined by peak expiratory flow rate (PEF), airway resistance (Raw) and the specific airway conductance (sGaw)-The aim of the present study was to compare the results obtained by the measurement of FEV|, determined by a Vitalograph, and total resistance to breathing (R,), determined by the opening interrupter method, as well as to examine the reproducibility ofthe responsiveness to inhaled allergen.…”

Guidelines for the standardization of bronchial provocation tests with allergens

“…Mosbech, using a Dermatophagoides pteronyssinus extract, standardized in biological units (BU/ml), adopts a pulmonary threshold from 1 to 10,000 BU/ml (47). Frolund et al (29) use 100,000 SQ, Units/ ml as top dose .giving a reproducible test. Melillo uses a top dose of 3200 arbitrary units (45), with D. pteronyssinus, while the top dose with grass pollen extract is significantly lower: 80 arbitrary units (5).…”