Systemic Lupus Erythematosus (SLE) is a widespread autoimmune disease for which early diagnosis is paramount in improving clinical outcomes. In this project, we used the de-identified patients from Epic Cosmos to retrieve the ICD code for SLE, checked data quality based on the EULAR/ACR classification systems, created an approach to determine the SLE patients, and performed statistical analyses on lab tests and clinical characteristics. Our preliminary results showed that clinical notes must be reviewed to improve the completeness, as structured EHR data fields provide limited information in determining if a patient meets the established classification criteria.