infectious diseases
Immunologic Tests for Infectious Disease
Precipitation tests
Precipitation tests measure an antigen or antibody in body fluids by the degree of visible precipitation of antigen-antibody complexes within a gel (agarose) or in solution. There are many types of precipitation tests (eg, Ouchterlony double diffusion, counterimmunoelectrophoresis), but their applications are limited. Usually, a blood specimen is mixed with test antigen to detect patient antibodies, most often in suspected fungal infection or pyogenic meningitis. Because a positive result requires a large amount of antibody or antigen, sensitivity is low. 