A new whole-scolex complement-fixation test for hydatid disease.

The sensitivity of indirect agglutination tests for the diagnosis of human hydatid disease, although high, is not sufficient. Furthermore, the general use of hydatid fluid as antigen is responsible for some false positive reactions. Scolex extracts have been shown to increase specificity, but less attention has been paid to whole-scolex antigens. The author describes a new whole-scolex complement-fixation test that, like other scolex tests, is more specific than tests using fluid antigen. Its sensitivity is at least equal to that of the hydatid fluid latex-agglutination test, and is higher than that of the fluorescent-antibody, the scolex extract latex, and the hydatid fluid complement-fixation tests.The new test is also of interest since particulate antigens are uncommon, compared with soluble antigens, in complement-fixation techniques.