The presence of antimitochondrial antibody was determined by an indirect immunofluorescence assay (IIFA) and a quantitative complement fixation test (CFT) in 2,302 sera. This survey enabled us to calculate the sensitivity, specificity, positive and negative predictive values of the two techniques. It seemed valuable to use both techniques as the IIFA was more sensitive than the CFT whilst the CFT was more specific than the IIFA.