Patent ID: 8859265

Claim:
A lateral flow immunoassay device for qualitative or quantitative analysis of an analyte of interest in a whole blood sample, the device comprising: a base member; and a horizontal array disposed on said base member, the horizontal array comprising: (i) a sample receiving pad being located on one end of the base member, having pores having an average pore size of 30 to 150 micrometers, which receive a whole blood sample, and which comprises a polycation which separates a red blood cell from the whole blood sample, thereby impeding passage of the red blood cell; (ii) a conjugate pad being distinct from the sample receiving pad, being in contact with the sample receiving pad, having pores having an average pore size of 6 to 11 micrometers, and comprising a diffusively bound conjugate, which forms a first immuno-complex with an analyte of the blood in the conjugate pad, the conjugate comprising a first binder specific to the analyte, and a label; (iii) a flow delaying pad being distinct from the conjugate pad, being in contact with the conjugate pad, having pores having an average pore size of 2 to 5 micrometers, and which receives from the conjugate pad the blood containing the analyte and the conjugate which are not yet combined each other, and the first immuno-complex; and (iv) a wicking membrane being in contact with the flow delaying pad, and having a second binder, which is immobilized in a test line of the wicking membrane, is specific to the analyte, and which combines with the first immuno-complex to form a second immuno-complex fixed to the test line, and which receives the blood from the flow delaying pad; and wherein a relation between average pore size (P 1 ) of the sample receiving pad, average pore size (P 2 ) of the conjugate pad, and average pore size (P 3 ) of the flow delaying pad is as follows: P 1 >P 2 >P 3 .