Used in immunological research to quantify indoleamine 2,3-dioxygenase 1 (IDO1) levels in biological samples such as serum, plasma, cell lysates, and tissue homogenates. IDO1 is a key enzyme involved in immune regulation, particularly in suppressing T-cell responses and promoting immune tolerance. This ELISA kit enables researchers to study IDO1 expression in contexts like cancer immunology, autoimmune diseases, infectious diseases, and pregnancy. It is widely used in preclinical studies to evaluate the effectiveness of IDO1 inhibitors and to understand the role of IDO1 in tumor microenvironments and inflammatory conditions. The assay provides a sensitive and specific method for monitoring changes in IDO1 concentration, supporting biomarker discovery and therapeutic development.