Evaluation of Meridian TRU Legionella®, a new rapid test for detection of Legionella pneumophila serogroup 1 antigen in urine samples

We evaluated the ability of a new antigen test (TRU Legionella® assay, Meridian Bioscience, Cincinnati, OH, USA) to detect Legionella pneumophila serogroup 1 antigen in urine. The results were compared with those obtained with the Binax NOW® urinary antigen test (Binax, Portland, ME, USA). The sensitivities and specificities were 73 % [95 % confidence interval (CI), 65 to 81 %] and 100 %, respectively, for the Meridian TRU Legionella test and 77 % (95 % CI, 68 to 84 %) and 100 %, respectively, for the Binax NOW urinary antigen test. The sensitivity of the Meridian TRU Legionella test increased to 81 % if tests were re-examined after 60 min of incubation. Prolonged incubation did not affect the specificity. We conclude that both assays evaluated have similar performance characteristics and are suitable for the rapid diagnosis of Legionnaires’ disease.