EVALUATION OF AN ELISA KIT FOR THE SERODI AGNOSIS OF LEGIONNAIRES-DISEASE

The presence of anti-Legionella antibodies was studied comparatively i n 81 sera with a commercially available ELISA kit (containing serogrou ps 1 to 6 as antigens) and the indirect immunofluorescence assay (IFA) with serogroup 1. The values obtained with the ELISA method were conv erted into immunofluorescence titers by using standard sera. Results o f 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 ser ogroups other than 1, antibodies were detected in 5 cases with ELISA a nd in none with IFA.