CHOC Children's
RESPIRATORY DISORDERS :: Cystic Fibrosis

Diagnosis of Cystic Fibrosis

How is cystic fibrosis diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for cystic fibrosis may include the following:

  • sweat (chloride) test - a test to measure the amount of chloride in the sweat. The test is performed by placing a solution on the forearm (or the thigh if the child is too small) and attaching electrodes. The skin is stimulated to sweat with a mild electric current, which does not cause pain or harm your child. The sweat is collected onto a gauze pad and analyzed. Higher than normal amounts of chloride may suggest cystic fibrosis. The sweat test is not painful and usually causes minor discomfort.
  • blood tests - blood or cheek scraping cells can be tested for mutations in the CFTR gene. Other blood tests can asses infection, and involvement of certain organs.
  • chest x-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
  • pulmonary function tests - diagnostic tests that help to measure the lungs' ability to exchange oxygen and carbon dioxide appropriately. The tests are usually performed with special machines that a child must breathe into.
  • sputum cultures - a diagnostic test performed on the material that is coughed up from the lungs and into the mouth. A sputum culture is often performed to determine if an infection is present.
  • stool evaluations - to measure stool fat absorption.
  • pancreatic function tests

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It is important to remember the health information found on this website is for reference only not intended to replace the advice and guidance of your healthcare provider. Always seek the advice of your physician with any questions you may have regarding a medical condition. If you think you may have a medical emergency, call your physician or 911 immediately.

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