Abstract: Crude extract of Periplaneta americana was prepared by liquid nitrogen grinding. After being purified with DEAE Sephadex A-50 ion exchange chromatography， the protein content of the extract was determined and the extract solution was prepared at gradient concentrations. The crude extract and purified allergen at different concentrations were dotted respectively on nitrocellulose （NC） membrane. Patient serum， bio-IgE， sa-HRP， luminal regents were added to the membrane. The chemiluminescence was displayed by exposing to X-film. The result revealed that the minimum protein content of crude Periplaneta americana extract detected by CLIA is 0.87μg/ml， with 90% accordance to skin test positive patients， and 100% accordance to those with negative skin test and ELISA detection.

Key words: Periplaneta americana, Specific allergen, sIgE, Chemiluminescence, Immunoassay