Methods and kits for measuring a component to be measured by reacting the component in the presence of a fatty acid alkanolamide, with a first antibody which binds to the component, then reacting a labeled second antibody that binds to the component so as to form an immunocomplex comprising the first antibody, the component and the labeled second antibody. The amount of the label in the formed immunocomplex is measured and correlated to the amount and concentration of component.