gel diffusion

Immunochemical method for determining presence of antigen in a specimen. Antigen & antibody are a allowed to diffuse through a semisolid medium such as agar or agarose. When the leading fronts of diffusion of antigen & antibody overlap (& the antigen binds to antibody) formation of a precipitin line will begin. The precipitin line will occur when the antibody is in slight excess.

References

Tietz Textbook of Clinical Chemistry, 2nd ed. Burtis CA & Ashwood ER (eds), WB Saunders Co, Philadelphia PA, 1993, pg 290