Used in immunology research to quantitatively measure soluble CD31 (PECAM-1) levels in biological samples such as serum, plasma, or cell culture supernatants. The kit helps assess endothelial cell activation, leukocyte migration, and vascular integrity in studies related to inflammation, angiogenesis, and autoimmune diseases. It is also applied in cancer research to investigate tumor angiogenesis and metastasis, as CD31 is involved in cell adhesion and signaling within the vascular system. The assay supports high-throughput screening and biomarker validation in preclinical studies.