The immunochromatographic assay operates on the principle of antigen-antibody interactions. The test strip typically consists of a sample pad, a conjugate pad, a nitrocellulose membrane, and an absorbent pad. When a sample is applied, it migrates along the strip by capillary action. Gold nanoparticles or colored latex beads conjugated with antibodies bind to the target antigen. The complex then migrates to the test line, where immobilized antibodies capture it, leading to a visible line indicating a positive result. A control line confirms the test's validity.
