[Solid-phase immunoenzyme analysis (ELISA)--a test for diagnosing Q fever (comparison with the complement fixation and immunofluorescence methods)].

Purified phase I Coxiella burnetii corpuscles treated chemically in different ways (by potassium periodate, mild acid hydrolysis or trichloroacetic acid) were compared by ELISA for their ability to detect phase II (directed to antigen 2) and phase I (directed to antigen 1) antibodies in sera from human Q fever convalescents. As to the absorbance values, the most sensitive was the antigen obtained by mild acid hydrolysis (0.1 mol/l HCl for 30 min. at 100 degrees C), followed by phase I corpuscular antigen treated trichloroacetic acid. Phase I antigen treated by K10(4) gave lower absorbance values. The performances of the commonly used complement fixation test and the more recently developed indirect immunofluorescence test were compared on 45 human sera. Immunofluorescence revealed specific antibodies in 62.2% of the sera. In the complement fixation test only 2.2% of sera were positive. ELISA proved superior (76.8% positive sera) to the immunofluorescence and complement fixation tests in detection of Q fever.