Anti-Kappa recognizes surface immunoglobulin on normal and neoplastic B-cells, and has been indicated as a potential aid in the identification of leukemias, plasmacytomas, and certain non-Hodgkin’s lymphomas, where the expression of a single light chain class is restricted. The determination of light chain ratio is critical in evaluating B-cell neoplasms, as the majority of B-cell lymphomas express either kappa or lambda light chains, while a mixture of kappa and lambda is characteristic of reactive proliferations. In paraffin-embedded tissue, Anti-Kappa displays strong staining of kappa-positive plasma cells, as well as cells that have absorbed exogenous immunoglobulins.