Diagnosis and Testing
How do I get tested for cystic fibrosis?
The sweat chloride test is the most common way (gold standard) to test for cystic fibrosis (CF). Levels of chloride above 60 mg/mL are considered diagnostic for cystic fibrosis. Sweat testing should be performed at a Cystic Fibrosis Foundation (CFF) accredited care center. To find a center near you, visit the CFF's website. DNA testing can also be offered to look for genetic changes (mutations) within the CFTR gene. Some DNA testing looks for common mutations (gene changes) seen in individuals with cystic fibrosis, while other DNA testing called sequencing looks at the whole CFTR gene to find any changes. Newborn screening looks for babies with unusually high immunoreactive trypsinogen (IRT) levels. In some states, the newborn screening test also includes testing for the most common mutations known to cause cystic fibrosis. If you and your partner are known to be carriers for cystic fibrosis, the fetus can be tested for cystic fibrosis during the first trimester of pregnancy through a test called a chorionic villi sampling (CVS) or later in pregnancy through a test called an amniocentesis. Your doctor can help you find specialists in your area where you can get testing if needed.