Automated complement fixation with low reagent consumption.

A microvolume automated (continuous-flow) system for the detection of complement-fixing antigen or antibody was evaluated. The model complement fixation test used was the detection of deoxyribonucleic acid antibody, and comparisons were made with a manual procedure. An "automatic two-dilution" feature of the apparatus was not used because of the clinical need for antibody titers. The system proved useful for the detection and estimation of anti-deoxyribonucleic acid antibody in patients with systemic lupus erythematosus and, indeed, accomplished this with low reagent consumption, a useful feature not available in "older" continuous-flow complement fixation systems.