Use of latex agglutination technique for detecting Legionella pneumophila (serogroup 1) antibodies

Following the outbreak of Legionnaires' disease in Stafford in 1985, 500 serum samples were submitted to the indirect immunofluorescence antibody test and a latex agglutination. Latex agglutination using ultrasonically disrupted Legionella pneumophila antigens coupled to latex particles, proved a rapid, simple method for detecting circulating antibodies to L pneumophila in a one minute slide latex agglutination test. There was good correlation with the indirect immunofluorescence antibody test (IFAT), and the specificity and sensitivity with respect to a diagnostic result were 98.3% and 97.6%, respectively, using a series of well characterised sera. The latex agglutination test seems well suited as a screening test for presumptive cases of Legionnaires' disease; the latex reagent is easy to prepare and seems to remain stable at 4 degrees C for up to six months.