As a preliminary step before performing the assay, some competitive-binding assays either adjust the pH of the patient sample or add an excess of a ligand that is similar to that being measured.Which of the following correctly describes the purpose for these preliminary steps?

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Quizplus · Accepted Answer

Many ligands measured in competitive-binding assays are found in the blood stream with a certain percentage bound to their respective endogenous serum binding proteins.Prior to analysis, these ligands must be displaced from the binding proteins to allow for measurement of the total ligand concentration.One method to address this is to alter the conformation of the binding protein by changing the pH of the reaction mixture.This conformational change will cause release of the ligand from the protein.This same result may also be achieved by adding an excess of a different ligand of similar chemical structure that will bind with the antibody, freeing the ligand of interest.

As a Preliminary Step Before Performing the Assay, Some Competitive-Binding