Development of a microplate ELISA for circulating E-selectin: assay characterization, comparison with a commercial kit, wand establishment of normal reference values

E‐selectin, an adhesion molecule, is detectable in the blood. Serum levels of E‐selectin can be a prognostic indicator for various malignancies. We developed a microplate enzyme‐linked immunosorbent assay (ELISA) for the detection of circulating E‐selectin by coating the microwell with monoclonal anti‐E‐selectin. We incubated the specimen and the biotinylated detecting antibody simultaneously, and used HPR‐conjugated streptavidin to generate a signal for quantification. The assay has a sensitivity of 3.8 ng/mL, and the coefficients of variation (CVs) for both within‐day and day‐to‐day precision were all