Inclusion Criteria:  Consenting people with cystic fibrosis of any age, genotype, transplant status and disease severity will be eligible to participate in the study. The study population is expected to be representative of the general CF population.  -  Exclusion Criteria:  There are no specific exclusion criteria other than refusal to give informed consent, or contraindication to venepuncture.  Participants already enrolled in a clinical trial are eligible for enrolment in this study. Inclusion in CAR-CF should not preclude enrolment in other observational clinical trial studies or clinical trials of an investigational medicinal product (CTIMP).