Specific diagnosis of exogenous bronchial asthma in adults. Comparison between case history, intracutaneous test, RAST, histamine release from basophil leucocytes, and bronchial provocation.

Twenty-two adults with extrinsic bronchial asthma were examined with 26 different allergens from five groups: house dust + mite (30 BP), animal dandruff (30 BP), pollen (12 BP), mould fungi (11 BP), and feather + cotton (10 BP). The same allergen batch was used for each allergen extract in all analyses. Based on the results of the single analyses: case history (CH), intracutaneous test (ST), RAST, histamine release from basophil leucocytes (HR), and the results of the analysis combinations and the "true diagnosis" bronchial provocation (BP), the sensitivity and specificity (SE and SP) were calculated and shown graphically. An evaluation of the diagnostic reliability of the single analyses and analysis combination was then possible. Generally, HR was the best individual analysis with very few false positive values and false negative values, followed by RAST, ST, and CH. None of them was able to predict allergy for feather + cotton. Otherwise, BP was positive when HR and rast reached scores 2 and 3 with the exception of RAST for animal dandruff. As regards ST, we had to reach score 3 in order to predict positive BP. CH would only provide the diagnosis with a maximum score in the pollen group. BP was positive in any analysis combination resulting in score 6 or more. ST appeared to be the most sensitive of the individual analyses. All the patients with ST score 0 showed negative BP for all allergen groups, whereas a corresponding sensitivity for HR score 0 was only achieved with animal dandruff, and for RAST score 0 for pollen only. In spite of the new analyses, BP is in many cases necessary if a definite diagnosis is required.