(                                                                                                                                          Equation   3                Percentage   of   receptor   binding   (ELISA)                Based   on   fluorescence   at   615   nm%   of   specific   binding=((sample   value-non-specific   binding)/(total   binding-non-specific   binding))×100Total   binding=biotinylated   PD-L 1   (no   antibody)Non-specific   binding=no   biotinylated   PD-L 1                                                                                                                                          Equation   4                Four   Parameter   logistic   calculation                Y=Bottom+(Top-Bottom)/(1+10^((LogIC 50-X)*HillSlope))X=logarithm   of   concentration .Y=specific   binding   (Equation   3)Top   and   Bottom=Plateaus   in   same   units   as   Y   (specific   binding))