The following is a summary of "Clinical Characteristics and Classification Criteria Performance in a Single-Center Cohort of 114 Patients With Immunoglobulin G4–Related Disease," published in the January 2023 issue of Rheumatology by Spandorfer, et al. IgG4-RD, also known as immunoglobulin G4-related disease, is a diverse fibroinflammatory disorder. The 2019 American College of Rheumatology (ACR)/European League