What type of assay might yield a negative result if the target analyte is present in high concentrations?

A competitive assay is designed to measure the concentration of a target analyte by utilizing the principle of competition. In this type of assay, the target analyte competes with a labeled analyte for binding to a limited quantity of a detection reagent, such as an antibody. When high concentrations of the target analyte are present, it can saturate the binding sites available on the detection reagent, leading to fewer labeled analytes binding. This results in a lower signal being detected, which can be interpreted as a negative or decreased result.

This phenomenon, often called the "hook effect" or "prozone effect," illustrates how the assay can produce an erroneous negative result when the concentration of the analyte is too high. Understanding this dynamic is crucial in interpreting results accurately, especially when dealing with assays that operate under competitive binding conditions. The other types of assays mentioned do not typically exhibit this negative result response when high analyte concentrations are present.