This immunoassay kit allows for the in vitro quantitative determination of Human PD-L1 concentrations in serum, plasma and other biological fluids. This assay employs an antibody specific for Anti-human PD-L1 coated on a 96-well plate. Standards and samples are pipetted into the wells and PD-L1 present in a sample is bound to the wells by the immobilized antibody. The wells are washed and biotinylated anti-human PD-L1 antibody is added. After washing away unbound biotinylated antibody, HRP-conju