Misdiagnosis of cystic fibrosis — Experience from Germany

BackgroundMisdiagnosis of cystic fibrosis (CF) is rare. We investigated patients with misdiagnoses of CF in Germany, and compared patients diagnosed before and after 1990.MethodsWe analysed data from the German CF quality assurance project and rechecked the data with CF-centre directors.ResultsBetween 1989 and 2004, CF diagnoses were withdrawn in 51 patients after 5.79 years (median), whose diagnosis was based on nonspecific symptoms between 1979 and 2001 at the median age of 4.33 years. CF transmembrane conductance regulator (CFTR) dysfunction was indicated by unreliable sweat tests (45.1%), pathologic sweat chloride (37.3%), genetic tests (3.9%), and nasal potential difference measurements (13.1%). Patients diagnosed after 1990 were older (6.13 vs 1.21 years), more frequently fulfilled the diagnostic criteria (77.4% vs 20%) and experienced respiratory symptoms (83.9% vs 50%).ConclusionsTo detect misdiagnoses of CF, CF-centres should re-evaluate patients with atypical courses and new or transferred patients.