[The practical assessment of complement involvement in anaphylactoid reactions].

While no single test is entirely satisfactory for the investigation of anaphylactoid response to intravenous anaesthetic drugs, changes in plasma chemistry are particularly easy to measure and may be carried out at centres remote from the clinical incident. Analysis should be carried out on a sequence of blood samples taken into EDTA over the 24 hours following such reaction. Few reactions are classical Type I, IgE antibody mediated, reactions and most involved the complement proteins in some specific manner. By measuring changes in the levels and activity of the complement proteins, particularly C3, C4 and C5, between samples, it is possible to deduce the likely mechanism of a reaction and thus to advise more wisely on future treatment of the patient. Although levels of any plasma protein may be readily measured by single radial immunodiffusion (Mancini technique) using appropriate specific antisera, one assessment of complement activity (degree of conversion) has until now largely been restricted to technically exacting Laurell immunoelectrophoresis. Two simple immunoelectrophoretic techniques are described here which do not require such expertise.