[Consensus on clinical application of immunoglobulin G4].

IgG₄ is a subclass of IgG. Elevated serum IgG₄ levels are an important serological feature of IgG₄ related diseases and serve as a serological marker for assessing disease activity and severity. The harmonization of IgG₄ detection is crucial for its clinical application. National Clinical Research Center for Dermatologic and Immunologic Diseases (Peking Union Medical College Hospital), Experimental Diagnosis Research Committee, Rheumatology and Immunology Physicians Committee of Chinese Medical Doctor Association, Autoantibodies Detection Committee, and Chinese Rheumatism Data Center have organized clinical and laboratory experts to draft this consensus, aiming to standardize IgG₄ detection and provide guideline for clinician and laboratory experts to appropriate utility and interpret IgG₄ results in China.