SAT. which stand for multiple antigen simultaneous test used enzyme- linked anti - human IgE and chemiluminogenic substate to determine IgE. This system is characterized by simultaneous analysis of multiple allergen items. up to 35. together with TIgE detemnation. We evaluated the usefulntess of this MAST system by using 91 serum sample obtained from patients with allergic disseases. It was found that there were statistically significant correlation between IgE antibodyquantification by MAST and RAST.It was also evaluated how many allergen-SIgE antibodies could be detected in one serum sample.These results indicate the clinical usefulness of the MAST allergy system in detecting IgEantibodies in allergic subj ects.