(a). NSB (non-specific binding): This represents signal from non-specifically bound peroxidase conjugate in a competitive immunoassay. This signal is generated from conjugate retained on the plastic itself, and the background signal from the substrate.
(b). B0 (binding for the zero standard, maximum binding well): This represents the maximum signal from enzyme captured by the specific antibody in competitive ELISA or CLIA immunoassays. All other standards and samples are expressed as a percentage of this value.
(c). Zero Standard (background signal for sandwich assay): In an immunometric assay, this represents the minimum signal from the assay. The Zero Standard becomes part of your standard curve.