With the ChemiKine assay system, sheep polyclonal antibodies generated against human NT-3 are coated onto a microplate and are used to capture NT-3 from a sample. NT-3 specific, biotin conjugated, mouse monoclonal antibodies detect the captured NT-3. After addition of streptavidin-enzyme, substrate and stop solution the amount of NT-3 is determined. The standard curve demonstrates a direct relationship between Optical Density (OD) and NT-3 concentration: i.e., the higher the OD the higher the NT-3 concentration in the sample.