TY - JOUR T1 - Diagnostic value of serological tests against <em>Pseudomonas aeruginosa</em> in a large cystic fibrosis population JF - Thorax JO - Thorax SP - 689 LP - 693 DO - 10.1136/thx.2005.054726 VL - 61 IS - 8 AU - G A Tramper-Stranders AU - C K van der Ent AU - M G Slieker AU - S W J Terheggen-Lagro AU - F Teding van Berkhout AU - J L L Kimpen AU - T F W Wolfs Y1 - 2006/08/01 UR - http://thorax.bmj.com/content/61/8/689.abstract N2 - Background: Serological methods to monitor Pseudomonas aeruginosa colonisation in patients with cystic fibrosis (CF) are advocated but the diagnostic value of a commercially available P aeruginosa antibody test to detect early and chronic P aeruginosa colonisation in a non-research setting has not been assessed.Methods: Colonisation with P aeruginosa was estimated by regular culture of sputum or oropharyngeal swabs during three consecutive years in 220 patients with CF aged 0–65 years. Commercially available ELISA tests with three P aeruginosa antigens (elastase, exotoxin A, alkaline protease) were performed at the end of the study period. In a subgroup of 57 patients (aged 4–14 years) serological tests were performed annually.Results: Using culture as the reference standard, the ELISA tests using the advised cut off values had a sensitivity of 79% and a specificity of 89% for chronic colonisation. Receiver-operator characteristic curves were created to optimise cut off values. Applying these new cut off values resulted in a sensitivity of 96% and a specificity of 79%. All three individual serological tests discriminated well between the absence and presence of chronic P aeruginosa colonisation. The sensitivity of the individual antibody test was 87% for elastase, 79% for exotoxin A, and 76% for alkaline protease. First colonisation was preceded by positive serological results in only five of 13 patients (38%).Conclusion: In patients with CF, serological tests using specific antigens are sensitive for diagnosing chronic P aeruginosa colonisation. However, the failure of serological tests to detect early colonisation in young patients emphasises the need for continued reliance on cultures. ER -