The high dose hook effect refers to measured levels of antigen displaying a significantly lower absorbance than the actual level present in a sample.
This appears when a simultaneous ELISA assay is saturated by a very high concentration of sample antigen binding to all available sites on both the solid phase antibody as well as the detection antibody and thereby preventing the sandwich-formation. The antigen-saturated detection antibodies in solution will be washed off giving a falsely low signal. A “hook” is observed in the curve when data is plotted as a signal versus antigen concentration.
To learn more about the ELISA procedure watch this short video: https://www.mercodia.se/videos