The microtiter plate provided in this kit has been pre-coated with an antigen. Standards or samples are then added to the appropriate microtiter plate wells with a Horseradish Peroxidase (HRP)-conjugated secondary antibody. After TMB substrate solution is added, those wells that contain Anti-Growth Hormone Antibody (Anti-GHAb) will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450nm ± 10nm. The concentration of Anti-Growth Hormone Antibody (Anti-GHAb) in the samples is then determined by comparing the O.D. of the samples to the standard curve.