Four modifications of the micro agar diffusion precipitin test.

Abstract

Abstract Four basic modifications of the Wadsworth type of micro agar diffusion precipitin test are described to illustrate its various uses as an analytic tool for clinical and biologic laboratories. The first, a single-diffusion technique, can be used to determine values similar to the classic optimal proportion ratio for one or more antigen-antibody systems in a single test. The second is a double diffusion quantitative technique particularly useful in the measurement of antigen or antiserum reactivity for several unequally reactive systems at one time. The third modification is a very sensitive comparator technique with excellent resolution which has been devised in a way to maximize the chances of precipitin band convergence under adverse conditions such as obtain when a complex mixture of antigens which vary widely in concentration is being compared with another similarly complex antigen mixture against a standard antiserum. For the fourth modification, a Plexiglass matrix has been designed as the key piece of apparatus in a very simple but highly sensitive microimmunoelectrophoretic technique particularly adaptable to routine use.