Used to measure levels of interleukin-31 (IL-31) in human biological samples such as serum, plasma, or cell culture supernatants. It is primarily applied in research settings to study inflammatory and immune-mediated diseases, especially those involving itching and skin conditions like atopic dermatitis. The kit helps researchers understand the role of IL-31 in disease progression and response to treatment. It is also used in clinical studies to evaluate the effectiveness of new anti-inflammatory or anti-pruritic drugs by monitoring changes in IL-31 concentrations.