Background@#Despite the autologous serum skin test (ASST)and autologous plasma skin test (APST) is widely used test accessingwhether a patient with chronic spontaneous urticaria(CSU) has autoreactivity or not, the clinician often encounterdifficulty making correlation between the test result and clinicalimplications. @*Objective@#This study was aimed to findany clinical and laboratory findings related to the ASST andAPST response. Agreement and correlation between the twotests was also analyzed. @*Methods@#A retrospective study wasconducted on 300 CSU patients who underwent ASST, APST.The subjects were divided into four groups according to theskin test result. Also, the degree of serum and plasma responsewas recorded. @*Results@#Both ASST and APST positivegroup had shorter duration of the disease, higher incidenceof at least one episode of angioedema than negative group.There were no significant differences in the positivity for autoantibodiesincluding antinuclear, ds-DNA, and thyroid-relatedbetween the two groups. The predicted positive rate ofASST and APST according to age showed bimodal peak and decreasing pattern according to disease duration. Predictedpositivity of both tests declined with increase in total immunoglobulineE (IgE) level. In the correlation study, the twotests showed high correlation coefficients. @*Conclusion@#ASSTand APST positivity may be related to disease duration andseverity of CSU. The two tests showed a generally consistentresult. Autoreactivity may be gradually lost as disease continues.We suggest the autoreactivity in CSU could arise independentlyfrom IgE mediated immune process.