Evaluation of a novel urinary antigen test kit for diagnosing Legionella pneumonia.

OBJECTIVES The aim of this study was to evaluate the diagnostic utility of a novel test kit that could theoretically detect all serogroups ofLegionella pneumophila for diagnosing Legionella pneumonia compared with existing kits. METHODS This study was conducted in 16 hospitals in Japan from April 2016 to December 2018. Three urinary antigen test kits, including the novel kit (LAC-116), Binax NOWLegionella (Binax), and Q-line Kyokutou Legionella (Q-line), were used. In addition, culture and nucleic acid detection tests of sputum and serum antibody tests were performed where possible. The diagnostic accuracy and correlations of the novel kit with the two existing kits were analyzed. RESULTS In total, 56 patients were diagnosed withLegionella pneumonia. The sensitivities of LAC-116, Binax, and Q-line were 79%, 84%, and 71%, respectively. The overall match rate was 96.8% between LAC-116 and Binax and 96.4% between LAC-116 and Q-line. One patient had L. pneumophila serogroup 2, and only LAC-116 showed a positive result, whereas Binax and Q-line did not. CONCLUSIONS The novelLegionella urinary antigen test kit was useful for diagnosing Legionella pneumonia. In addition, it could detect Legionella pneumonia caused by non-L. pneumophila serogroup 1.