IgE total is a one-step immunoassay, based on the principle of the sandwich method.
IgE molecules present in the sample and the labeled enzyme-anti-IgE monoclonal antibodies in the conjugate compete for binding to the capture antibody on the anti-IgE coated microplate. The enzyme activity in the antibody-bound fraction is directly proportional to the IgE concentration.
The unbound components are removed by washing. After addition of the solution containing
TMB and hydrogen peroxide, the wells with bound conjugate develop a blue color which is converted to yellow after the reaction has been stopped with sulphuric acid.
The color intensity is directly proportional to the concentration of the IgE molecules in the specimen and can be read at 450 nm.