Testing of a patient for pathogenic cystic fibrosis transmembrane conductance regulator variants for the purpose of investigating, making or excluding a diagnosis of cystic fibrosis or a cystic fibrosis transmembrane conductance regulator related disorder when requested by a specialist or consultant physician who manages the treatment of the patient, not being a service associated with a service to which item 73347, 73348, or 73349 applies. The patient must have clinical or laboratory findings suggesting there is a high probability suggestive of cystic fibrosis or a cystic fibrosis transmembrane conductance regulator related disorder.