How are lateral flow immunoassays (LFIAs) developed?

A lateral flow immunoassay (LFIA) is a simple diagnostic device based on the chromatography-like migration of a labeled analyte through multiple membranes, including a sample pad, conjugation pad, detection pad, and absorbance pad, ending in the visible result of an immobilized captured reagent. The sample application pad is the first application that comprises sample volumes. This application is made of cellulose fiber, that is vital in regulating the distribution of the sample. The conjugate release pad is where the detection agent is stored. The conjugate pad is made of non-woven glass fiber. If the target analyte is present, the labeled antibodies will bind to it and continue to move to the detection pad, where the materials are captured by immobilized antibodies at a test line (T-line). The intensity of the color is later seen in the developed test line. A subsequent control line (C-line) is used to indicate that the solution has sufficiently migrated. Finally, the absorbent pad absorbs excess sample. The assays are developed based on two formats-competitive and direct.