[Comparison of five commercial assays for the detection of Legionella pneumophila antigens in urine].
OBJECTIVE
Antigenuria detection is the main approach for diagnosing Legionella infections. The aim of this study was to compare 5 commercially available methods for detecting Legionella pneumophila soluble antigens in urine.


METHODS
Seventy-one urine samples were tested, 62 from patients with bacterial infection and 9 from patients with respiratory syncytial virus infection. All samples were assayed for the presence of L. pneumophila by immunoenzymatic (ELISA) (Binax and Bartels), and immunochromatographic (IC) (Binax, SAS and Uni-Gold) methods.


RESULTS
Identical results (35 positive and 17 negative) were obtained by the 5 assays in 52 samples (73.2%). Samples showing discrepant results were classified by the majority criterion, and/or other laboratory results (serology), and/or epidemiological findings. On this basis, 51 samples were ultimately classified as positive, and 20 as negative. Sensitivity values of ELISA-Binax, ELISA-Bartels, IC-Binax, IC-SAS and IC-Uni-Gold were 80.4, 100, 82.4, 86.3, and 70.6%, respectively. Corresponding values for specificity were 90, 95, 100, 95 and 100%.


CONCLUSIONS
The results indicate that the methods compared are all adequate for diagnosing Legionella infection, although some have certain limitations regarding sensitivity.
de Ory
Fernando
F
Servicio de Microbiología Diagnóstica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, España. fory@isciii.es
Minguito
Teodora
T
D000907:Antibodies, Bacterial; D055910:Antibodies, Immobilized; D000942:Antigens, Bacterial / Q000652:urine*; D002845:Chromatography; D003101:Collodion; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007163:Immunosorbent Techniques; D016952:Legionella pneumophila / Q000276:immunology*; D007877:Legionnaires' Disease / Q000453:epidemiology / Q000652:urine*; D008297:Male; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial; D055910:Antibodies, Immobilized; D000942:Antigens, Bacterial; D003101:Collodion