Assessment of a new test to detect Legionella urinary antigen for the diagnosis of Legionnaires' Disease

Given that the rate of mortality by Legionella pneumonia increases in incorrectly treated patients, rapid diagnosis and early antibiotic treatment are needed. We have assessed the performance of a new enzyme immunoassay (ETA) test (Bartels Inc. Trinity Biotech Company, Wicklow, Ireland) to detect Legionella pneumophila antigen in urine comparing it to Binax EIA (Binax, Portland, Maine). We also evaluated the capability of both EIAs to detect extracted soluble antigens of Legionella strains. Using nonconcentrated urine samples (NCU) the sensitivity of Bartels ETA was 74.1% (66/89) and the sensitivity of Binax ETA was 51.7% (46/89). The sensitivity of both ETA tests were 91.5% (54/59) using concentrated urine samples (CU). Specificity of both ETA tests was 100% in NCU and CU. Bartels ETA was able to detect all serogroup L. pneumophila antigens, achieving a higher sensitivity in the case of L. pneumophila serogroup I soluble antigen. The new ETA was found to be a useful test for the rapid diagnosis of Legionella pneumonia. being a better alternative to the Binax EIA if NCU is used. (C) 2001 Elsevier Science Inc. All rights reserved.