The present invention provides novel mutations identified in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that can be used for a more accurate diagnosis of cystic fibrosis (CF) and CF related disorders. Methods for testing a sample obtained from a subject to determine the presence of one or more mutations in the CFTR gene are provided wherein the presence of one or more mutations indicates that the subject has CF or a CF related disorder, or is a carrier of a CFTR mutation.