Immunoassay is a bioanalytical method based on the reaction of antigen and antibody.
These processes are being used more and more widely today, for example, in the field of pharmaceutical research, therapeutic treatments, and environmental biology to determine the presence, quantity or functional activity of an analyte (target molecule). The method is characterized by high sensitivity, high throughput and specificity.
The immunoassay can be designed in different forms depending on the target molecule and customer needs (competitive, sandwich, quantitative, qualitative, measurement range, sensitivity, performance, time, material used, sample preparation, price, etc.). The method allows a quantitative or qualitative determination of one or more analytes simultaneously from a single sample. Labeling material (fluorescent dye, enzyme, etc.) is used in the measurement, the name of the method is based on the nature of the marking (RIA 1959, FIA, EIA, ELISA LIA, etc.)
Our most commonly developed and applied immunoassay is based on a competitive binding reaction in which a specific amount of labelled analytes (conjugates) and a variable amount of unlabelled analyte present in the sample compete for the specific binding sites of the antibody that can be immobilized or in the solution. Thus, by mixing and incubating the developed immunoanalytical reagents with the sample or standard solution, the antigen binds to the antibody and forms a complex. This complex can be separated from the unbound reactant fraction by physical or chemical separation techniques. The quantitative or qualitative determination is performed by measuring the labelled analyte (e.g., fluorescence or enzyme) in either the bound or the free fraction. By depicting the measured signal, the concentration of the sample analyte can be determined depending on the concentration of the standard solution.