A quality control study of CFTR mutation screening in 40 different European laboratories. The European Concerted Action on Cystic Fibrosis.

A quality control study was performed to determine the accuracy of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) mutation screening in 40 different genetic screening laboratories throughout Europe. A total of 9 different samples were investigated blindly by the participating laboratories. Only 25/40 laboratories, i.e. 62.5%, were able to type all samples correctly for the mutations for which they routinely screened. Only 2 of the 9 samples were correctly typed in all 40 laboratories. The lowest accuracy rate was 80% for 1 sample. 12.5% of the participating laboratories interpreted the F508C polymorphism as a true CF disease mutation and 23.5% interpreted the delta I507 mutation as a delta F508 mutation. For the delta F508 mutation, a false-negative result of 3.75% was obtained. It is clear that the accuracy of CFTR typing should be improved.