Abstract： Objective:To investigate the prognostic value of serum immunoglobulin E in emergency percutaneous coronary intervention(PCI)operation for ST-segment elevation myocardial infarction(STEMI).Methods:This study was a retrospective study, a total of 368 STEMI patients, 163 males and 205 females, aged(62.98±22.55)years old, with an age range of 23 to 74 years old, who attended the department of laboratory medicine and underwent emergency PCI at Fujian Province Ningde People′s Hospital from January 2019 to February 2021 were selected.Patients were divided into good prognosis group( n=321)and poor prognosis group( n=47)according to the prognostic outcome.General data and serum of anterior venous blood of elbow after PCI were collected from all patients, and serum immunoglobulin E concentration was measured by enzyme-linked immunosorbent assay.The correlation between serum immunoglobulin E concentration and STEMI prognosis was analyzed by Spearman correlation coefficient, the poor prognostic factors of STEMI was analyzed by logistic regression analysis, and the predictive value of serum immunoglobulin E on STEMI prognosisof factors affecting poor STEMI prognosis was analyzed by receiver operator characteristic(ROC)curve. Results:Serum immunoglobulin E concentration was higher in the poor prognosis group[(134.26±46.15)mg/L]than in the good prognosis group[(23.45±7.50)mg/L], with a statistically significant difference( P<0.05). In the good prognosis group, hypertension[13.7%(44/321)], diabetes[32.7%(105/321)], history of smoking[34.9%(112/321)], diastolic blood pressure[(114.10±11.08)mmHg, 1 mmHg=0.133 kPa], systolic blood pressure[(74.16±7.59)mmHg], fasting glucose[(5.84±1.05)mmol/L]compared with the poor prognosis group[29.8%(14/47), 76.6%(36/47), 63.8%(30/47), (121.02±10.59)mmHg, (82.05±8.42)mmHg, (8.43±1.23)mmol/L], with statistically significant differences( P<0.05). Serum immunoglobulin E concentration was correlated with poor prognosis of STEMI( ρ=0.56, P<0.05). Serum immunoglobulin E was an independent predictor of poor prognosis in STEMI patients( P<0.05). The area under the ROC curve for serum immunoglobulin E was 0.95(95% CI: 0.909 to 0.972, P<0.001), and the Yordon index was 0.85.The diagnostic sensitivity was 92% and the specificity was 93% using a positive threshold of 73.39 mg/L for serum immunoglobulin E as the diagnostic threshold. Conclusions:The detection of serum immunoglobulin E expression can be used as a potential marker for the prognosis of STEMI patients undergoing emergency PCI.