A centrifugal micro-fluidic device comprising at least one micro-fluidic structure, the micro-fluidic structure comprising: a sample chamber having a cross-section diameter increasing from a sample introduction inlet toward an outlet for receiving a fluid sample; a separation chamber connected to the sample chamber for centrifugation of the fluid sample for separation of a supernatant containing an analyte from the fluid sample; a first reaction chamber which is connected with the separation chamber and contains at least one labeling conjugate comprising a label and a binder, wherein the binder specifically binds to the analyte in the supernatant; a second reaction chamber which is connected with the first reaction chamber and contains a capture binder selected from a group comprising: antibody, antigen, receptor, ligand, oligonucleotide, hapten or aptamer; a buffer chamber which is connected with the second reaction chamber and contains an elution buffer, wherein the elution buffer dissociates an immune complex into the at least one labeling conjugate, the analyte and the capture binder; a waste chamber connected to and positioned downstream of the second reaction chamber for receiving impurities including an excess of a first immune complex as well as the analyte; a washer chamber connected to and upstream of the second reaction chamber containing a washing solution for washing away unreacted labeling conjugate and reaction residues; a detection chamber which is connected with the second reaction chamber for receiving the at least one dissociated labeling conjugate; a plurality of channels through which the first reaction chamber, second reaction chamber, buffer chamber and detection chamber are interconnected; and at least one valve which is positioned in at least one of the plurality of channels, and opens and closes the channel. a sample chamber having a cross-section diameter increasing from a sample introduction inlet toward an outlet for receiving a fluid sample; a separation chamber connected to the sample chamber for centrifugation of the fluid sample for separation of a supernatant containing an analyte from the fluid sample; a first reaction chamber which is connected with the separation chamber and contains at least one labeling conjugate comprising a label and a binder, wherein the binder specifically binds to the analyte in the supernatant; a second reaction chamber which is connected with the first reaction chamber and contains a capture binder selected from a group comprising: antibody, antigen, receptor, ligand, oligonucleotide, hapten or aptamer; a buffer chamber which is connected with the second reaction chamber and contains an elution buffer, wherein the elution buffer dissociates an immune complex into the at least one labeling conjugate, the analyte and the capture binder; a waste chamber connected to and positioned downstream of the second reaction chamber for receiving impurities including an excess of a first immune complex as well as the analyte; a washer chamber connected to and upstream of the second reaction chamber containing a washing solution for washing away unreacted labeling conjugate and reaction residues; a detection chamber which is connected with the second reaction chamber for receiving the at least one dissociated labeling conjugate; a plurality of channels through which the first reaction chamber, second reaction chamber, buffer chamber and detection chamber are interconnected; and at least one valve which is positioned in at least one of the plurality of channels, and opens and closes the channel.