Objective To evaluate the validity and predictive value of CAP specific IgE test system. Methods Five allergen-specific IgEs, i.e. , specific IgE to mites, mugwort pollens, hop pollens,cat epithelium and dander, and Alternaria alternate,were tested in selected randomly allergic and non-allergic patients by using CAP system. Results In 957 tests the sensitivity of specific IgE to the 5 allergens was 99.0% ,97.9% ,91.7% ,93.5% and 85.5% ,and the specificity was 96.2% ,95.8% ,93.0% ,97.0% and 91.7%. The positive and negative predictive values were greater than 94% and 80% respectively. Conclusion CAP system is of great potential value for diagnosis of allergenas.