Cystic Fibrosis | Diagnosis

How is cystic fibrosis diagnosed?

The first step in treating your child is forming an accurate and complete diagnosis. All newborns in Massachusetts — and most other states — are screened for cystic fibrosis (CF). If doctors suspect that your child has CF, they will want to perform a sweat test. This is to make an area of your child’s skin sweat enough so that doctors can collect some sweat and determine how much salt (sodium and chloride) is in it. A high level indicates CF. The test takes about 40-45 minutes from start to finish. 

Your child’s doctor may also order one or more tests.

  • Blood tests to test child’s blood cells for mutations in the CFTR gene. Other blood tests can assess infection and tell us whether other organs may be involved.
  • Chest x-rays
  • Pulmonary function tests to measure the lungs' performance. In these tests, your child will simply breathe into one or more special machines.
  • Sputum cultures are performed on the material that is coughed up from the lungs and into the mouth (often done to test for infection).
  • Stool evaluations to measure stool fat absorption.
  • Pancreatic function tests to assess the pancreas.

After all necessary tests, clinicians review and discuss what they have learned about your child's condition, then meet with you and your family to discuss the results and outline the best treatment options.