Used to detect and quantify levels of the TWEAK protein in human biological samples such as serum, plasma, or cell culture supernatants. This assay is commonly applied in research settings to study inflammatory diseases, autoimmune conditions, and cancer, where TWEAK signaling plays a role in cell death, inflammation, and tissue remodeling. It helps researchers evaluate disease progression, assess therapeutic responses, and understand the molecular mechanisms involving the TWEAK/Fn14 pathway.