Substrate for fluoroimmunoassay of biological fluids

An immunoassay method for determining or detecting the presence or absence of an immunogen comprising:

• (1) contacting a fluid suspected of containing said immunogen to a substrate useful for fluoroimmunoassays, said substrate comprising:
• (a) swellable, rehydratable protein binding material forming a three dimensional polymeric matrix;
• (b) first particulate light scattering centers distributed in the polymeric matrix which scatter all visible wavelengths of light;
• and
• (c) second particulate light scattering centers distributed in the polymeric matrix which scatter only fluorescent excitation light of a particular wavelength or frequency and absorb all other light;
• (2) incubating the fluid and substrate under conditions favoring binding of immunogen to said substrate;
• (3) adding a sample of a material known to specifically bind to the immunogen, said material having bound thereto a fluorescing dye molecule;
• (4) incubating the substrate with immunogen bound thereto with said sample under conditions favoring binding of said material to the immunogen;
• (5) removing non-bound material, and;
• (6) observing scattering of light from the fluorescing dye molecule or lack thereof, the presence of said scattering indicating presence of the immunogen, and lack of said scattering indicating absence of the immunogen: