Solid phase indicator red blood cells and method

A method and composition for use in preparing red blood cells for use as indicator cells to detect the presence of antigens and antibodies in biological fluids is the subject of the present invention. Freshly collected human or animal erythrocytes are washed six times with isotonic saline, and suspended to a hematocrit of four percent (volume/volume) with isotonic saline. An incomplete antibody, specific for the antigen or antibody to be detected, in a quantity less than that which would cause irreversible agglutination, is added to the erythrocyte solution. The mixture is incubated, washed, and suspended to a hematocrit of 3-5 (v/v) with isotonic saline. A second antibody, immuno specific for the first antibody and in an amount sufficiently great to immunologically bind substantially all of the antibody carrying red blood cells but not so great as to cause irreversible agglutination, is attached to the erythrocytes. This mixture is incubated, washed, and suspended to a hematocrit of 0.1-1% (v/v) in a media containing red blood cell nutrients. The resulting indicator red blood cells are used with solid phase immunological testing using various types of solid substrates.