In an unselected population of 133 young adults studied by prick testing to common allergens three groups were identified: eleven subjects with positive skin test responses and clinical symptoms of allergy; ten subjects only with positive skin tests and the remainder with negative skin tests.

All subjects with positive skin tests (with and without symptoms) were studied by RAST on the serum and nasal secretions. Specific and non-specific bronchial provocation tests (BPT) were also carried out.

The serum RAST was positive in all subjects with positive skin tests, and there was good correlation between high levels of circulating specific IgE and the presence of clinical symptoms.

The RAST of nasal secretions was negative in most symptom-free subjects and as a diagnostic lest it was slightly better than the serum RAST.

BPTs with extracts of the relevant allergens caused bronchospasm in every subject with a positive nasal secretion RAST. Only two subjects out of fifteen with a positive response were clinical asthmatics. Our results cast doubt on the clinical relevance of the BPT as it is usually conducted.