The naked emperor

One of the great religious divides in the world of cystic fibrosis (CF) is the use of serological tests to diagnose early infection with Pseudomonas aeruginosa. Two large Australasian groups have combined to deliver what should be the death blow to Pseudomonas serology. The AREST-CF cohort (annual bronchoscopy as a routine) was the discovery population, and the ACFBAL group (testing whether bronchoscopic guided treatment adds value to conventional therapy) was the validation set. Both commercial and in-house serological tests were used. The answer in both cohorts: serology has good negative predictive values, but is less good than flipping a coin when it comes to positive prediction of early infection. The tests are good for confirming the …