Which assay type typically produces results based on a competition principle?

The competitive assay is designed to produce results based on the competition between a target analyte and a labeled substance for a limited number of binding sites on a specific receptor or antibody. In this type of assay, the amount of signal generated is inversely related to the concentration of the target analyte in the sample. As the concentration of the analyte increases, it competes with the labeled substance for binding, leading to a decrease in the signal.

In immunoassays, while many can operate on a competitive principle, they also include non-competitive variants that do not rely on competition. Colorimetric assays primarily focus on changes in color to indicate concentration but do not inherently rely on a competition principle. Microbial assays involve the quantification of microorganisms and typically do not involve competitive principles in the same way that a competitive assay does. By focusing on the competitive nature of the binding interactions, the competitive assay type distinctly fits the description provided in the question.