Cautions

A diagnosis should not be made based on positive Legionella antibody results alone. Test results for Legionella antibodies should be interpreted in conjunction with the clinical evaluation and the results of other diagnostic procedures.

A positive result suggests infection with one or more of the groups 1-6 species; however, it is not possible to distinguish between species with the results of this enzyme-linked immunosorbent assay test alone.

Use of serogroups 1-6 for assessing antibody responses to different Legionella species and serogroups has not been established.

Cross-reactivity may occur in sera with infections due to other Legionella species.

Positive results may be due to cross-reactivity with an antibody generated as a result of non-Legionella infection. Serologic cross-reactions have been reported with Pseudomonas aeruginosa, several Rickettsia species, Coxiella burnetii, enteric gram-negative rods, Bacteroides species, Haemophilus species, Citrobacter freundii, and Campylobacter jejuni. Additionally, some reports indicate that a number of apparently healthy individuals may carry antibodies to legionellae; however, a positive result, along with clinical signs and symptoms may indicate possible Legionella infection. Additional testing to directly detect the organism, either through culture or nucleic acid amplification tests, is recommended to make a diagnosis of current infection.

The assay performance characteristics have not been established for matrices other than sera.

Although the conjugate is designed to detect human IgG, IgM, and IgA, it is not possible to determine which antibody is present with this assay.

The use of hemolytic, lipemic, bacterially contaminated, or heat-inactivated specimens should be avoided as erroneous results may occur.