Abstract: The invention provides a method of sandwich immunoassay comprising steps of, (a) forming a complex of an antigen and a first antibody by contacting the antigen with the first antibody which recognizes the antigen and which is labeled by a detectable labeling substance; and (b) fixing the complex formed in the step (a) to a solid phase by using a second antibody which recognizes the antigen and which is capable of binding to the solid phase, as well as a method for detecting an antigen in an analyte by using a method of sandwich immunoassay.

Abstract: The present invention is to present a sample analyzer which is capable of separate and dispose of the reaction container and the reaction liquid respectively even when magnetic particles are included in a reagent. The sample analyzer 1 comprises: a detector 16 for detecting the target substance by using a cuvette 300 which contains the target substance captured by the magnetic particle; an adsorption section 183 for magnetically adsorbing the magnetic particle in the cuvette 300; a liquid aspiration section 18 for aspirating a liquid in the cuvette 300 in a state in which the magnetic particle in the cuvette 300 is magnetically adsorbed by the adsorption section 183; and a disposal section 19 for accommodating the cuvette 300.