Test Plate for Toxoplasmosis.
IHA (Indirect hemagglutination) test plate for IgG antibodies directed against Toxoplasma gondii. The upper two lines of wells are the negative control, with the positive control and two positive samples below, at various dilutions. In wells labeled S, the red blood cells have been sensitized with T gondii antigen. The U rows of cells (unsensitized erythrocytes) are a further control that antibodies are directed at T gondii, not the sheep erythrocytes themselves - all the U wells on this plate are negative.
Smith MC (2006)