Counterimmunoelectrophoresis employing coccidioidin in serologic testing for coccidioidomycosis

Counterimmunoelectrophoresis, was performed for serologic testing for coccidioidomycosis, employing coccidioidin and spherulin as antigens. Results obtained by counterimmunoelectrophoresis were compared with results obtained by complement-fixation and radial immunodiffusion. Of the 37 sera positive by complement-fixation, 28 were positive by counter-immunoelectrophoresis utilizing coccidioidin, whereas only 11 were positive by counterimmunoelectrophoresis utilizing spherulin (although an additional 14 were positive with counterimmunoelectrophoresis employing spherulin when the quantity of spherulin was increased by 50 to 100%). Thirty-three of these complement-fixation-positive sera were positive by immunodiffusion. Counterimmunoelectrophoresis performed with coccidioidin detected antibodies to C. immitis in all patients who had complement-fixation titers greater than 1:4. When combined with latex agglutination, counterimmunoelectrophoresis utilizing coccidiodin had an 86% correlation with complement-fixation for the detection of positive sera.