[Evaluation of an ELISA technique for the serodiagnosis of legionnaires' disease].

The presence of anti-Legionella antibodies was studied comparatively in 81 sera with a commercially available ELISA kit (containing serogroups 1 to 6 as antigens) and the indirect immunofluorescence assay (IFA) with serogroup 1. The values obtained with the ELISA method were converted into immunofluorescence titers by using standard sera. Results of both methods were concordant in 83% of the sera when a cutoff value of 1/128 was used, and in 88% of the sera when the cutoff value was 1/128 for IFA and 1/256 for ELISA. In 6 other patients infected by serogroups other than 1, antibodies were detected in 5 cases with ELISA and in none with IFA.