[A study on EDTA antigens for detection of IgG antibodies to Legionella pneumophila].

The EDTA and Sonicate antigens used in ELISA for detection of IgG antibodies to Legionella Pneumophila serogroups 1-6 and Tatlock was evaluated. Sensitivity and specificity of EDTA antigens were compared with Sonicate antigens in three groups of subjects. In two serum samples from healthy employees, the Lp1 antibody titers with EDTA and Sonicate antigens were less than or equal to 1:160. Testing seven samples from patients indicated that four samples reacted with titers of 1:1280-2560 to Lp1 with EDTA and Sonicate antigens. But in another three samples, the antibody titers to Lp1 with EDTA antigen were lower 1-3 dilution than Sonicate antigen. One of the lowest titer to EDTA was 1:320 that was interpreted as positive. In all of the seven samples, the antibody titers to Lp4 and Tatlock raised to 1:640-2560 with sonicate antigens and significantly higher than the titers with EDTA antigens (1:320-640). The comparison between the EDTA and Sonicate antigens showed that when the antibody titer with EDTA antigens greater than or equal to 1:320 was regarded as a positive mark the sensitivity of EDTA antigens was similar to Sonicate antigens and the specificity was better than Sonicate antigens. Comparison of EDTA antigen was simple. It is worth to further study.