Detection of Australia-SH antigen in serum. A comparison of the electron microscopical, agar gel double diffusion, and complement fixation tests.

Presence of Australia-SH antigen in serum has been studied by agar gel double diffusion, electron microscopy and complement fixation tests. Serum from 30 patients suffering from serum hepatitis or infectious hepatitis, and serum from 10 apparently healthy blood donors have been included in the investigation. In serum from four of the patients with Australia-SH antigen positive serum hepatitis, the presence of the antigen has been studied during the course of the disease. The agar gel double diffusion test was less sensitive than the other two methods, although the sensitivity of this method was raised by increasing the amount of the serum sample to be examined. The present electron microscopical test seems to be at least as sensitive as the complement fixation test. However, the electron microscopical test may be less specific than previously believed.