Sensitivity and specificity of prick and intradermal testing in predicting response to nasal provocation with timothy grass antigen

OBJECTIVE: Examine the efficacy of epicutaneous and intradermal testing in predicting response to nasal provocation with timothy antigen. STUDY DESIGN AND SETTING: Prospective study. Subjects were tested with Multi-Test II (MT). Subjects with negative wheals were tested with a 1:500 intradermal injection of timothy. They had baseline assessment of nasal cross-sectional area (CSA) using acoustic rhinometry and underwent nasal provocation with increasing timothy concentrations. CSA was assessed and nasal visual analog scale (VAS) completed with each concentration. RESULTS: Sensitivity and specificity of MT in predicting nasal response to provocation were 87% and 86%. Intradermal testing increased sensitivity to 93%. Hierarchical linear modeling (HIM) demonstrated that subjects positive to skin testing had significant reductions in CSA and worsening VAS scores with increasing concentrations of nasally delivered antigen. CONCLUSION AND SIGNIFICANCE. Epicutaneous testing with the Multi-Test II offers 87% sensitivity and 86% specificity in assessing timothy grass reactivity.