The present invention relates to systems and methods for the rapid in situ determination of the existence of a hook effect and expansion of the dynamic range of a point of care immunoassay. For example, a system for identifying a hook effect and expanding the dynamic range of an immunoassay is provided that may include a primary sensor having first immobilized antibodies that may be configured to generate a first signal based on a presence or absence of a target analyte in a sample. The system may further include an attenuated sensor having second immobilized antibodies at a reduced concentration relative to a concentration of the first immobilized antibodies on the primary sensor and that may be configured to generate a second signal based on the presence or absence of the target analyte in the sample. The system may further include a processor configured to determine a presence of a hook effect in the immunoassay based on relative values of the first and second signals and optionally determine the target analyte concentration of the sample.