ABSTRACT
Polyclonal antibodies of di erent types are known to show a nity for speci c compounds. us, antibodies that can bind to a speci c substance to be analyzed are immobilized to the walls of the test tubes, plates, or microwells. Such test tubes and plates are commercially available and supplied in the test kit. A measured amount (between 10 and 50 μL) of sample or sample extract is added to one such test tube containing an assay diluent (a phosphate bu er). An equal volume of analyte-enzyme conjugate (commercially available and supplied in the kit) is then added to the test tube. e enzyme conjugate is a solution containing the same analytes covalently bound to an enzyme. e solution mixture is incubated or allowed to stand for a speci c amount of time. During this period, the enzyme conjugate competes with the analyte molecules for a limited number of antibody-binding sites in the test tube.
