Instrumented PVP‐Augmented Antiglobulin Tests

Washed normal, and allogeneic antibody‐coated, red blood cells were tested with specific antisera to IgG, IgA, IgM, IgD, IgE, x ‐ and Λ‐light chains, and C3 and C4 complement components. Tests augmented by addition of K‐90 polyvinylpyrrolidone (PVP) and performed on an AutoAnalyzer proved to be significantly more sensitive than comparable manual tests. All IgG allogeneic antibodies tested displayed both x ‐ and Λ‐light chains. One example of anti‐P2 (—Tj a ) coated normal red cells with all 5 classes of immunoglobulins. The detection of cell‐bound IgM Rh antibodies by anti‐IgM was associated with marked disruption of PVP‐mediated spontaneous agglutination of these coated cells. Agglutination by anti‐C4 was an excellent indicator of classical complement fixation at the red cell surface. When both C3 and C4 agglutination was observed, C 4 was usually stronger than C3.