Comparison of skin prick test and serum specific IgE measured by ImmunoCAP system for various inhalant allergens

Abstract

Purpose: It appears that much of the discordance between skin prick test (SPT) and ImmunoCAP in clinical practice. We investigated the comparison and correlation between SPT and ImmunoCAP for inhalant allergens. Methods: A total of 1,400 patients who were tested SPT and ImmunoCAP were recruited from June 2011 to May 2014 in Dong-A University Hospital, and the results of two assays were compared for 17 inhalant allergens. For SPT, mean wheal size≥3 mm or allergen/ histamine≥1 at 15 minutes, and the result of ImmunoCAP of ≥0.35 kU/L was considered positive, respectively. Results: Of the study subjects, bronchial asthma was 29.3%, rhinitis 36.8%, atopic dermatitis 0.6%, and chronic urticaria 4.3%. The agreement rate of between two assays was 77.4%. When ImmunoCAP was compared with SPT as the reference, the sensitivity, specificity was 75.5% and 80.0%, respectively. Significant correlation was observed (r=0.59), and birch, mugwort, Japanese hop, house dust mites, and cockroach showed very strong correlation (r>0.7). Conclusion: The agreement, sensitivity, and specificity between SPT and ImmunoCAP was various according to allergens. We should determine the clinical relevance of the allergen sensitization using both SPT and ImmunoCAP not alone with combination of clinical symptoms.