Diagnosis

The are a variety of measures in place to test for Cystic Fibrosis.  All newborns in the United States are screened for CF by either a blood test or a genetic test.  The blood test assesses pancreas function, while the genetic test indicates whether the CFTR gene is faulty.  If one of these newborns screenings indicates an abnormality, the infant will undergo a sweat test between two and four weeks of life.  During the sweat test, a technician will apply a chemical solution to a small area of the arm or leg.  This chemical does not pose a risk to the child.  An electrode is placed on the area and a mild electric current is applied to induce sweating.  This part of the procedure takes about 5 minutes and the child may feel some tingling or warmth, but it is not strong enough to cause pain or damage.  The sweat is collected on a piece of filter paper or gauze and then sent to the lab for evaluation. The lab is checking for chloride levels in the infant's sweat.  Some physicians may order the test to be performed twice for verification.  This test is safe and reliable.  It has been the "Gold Standard" in CF diagnosis for over fifty years.  The entire test takes about an hour, but may take longer.  The child should not have lotion or ointment applied to the skin for 24 hours before the test.  Otherwise no changes in diet or medications need to be made.  Once a positive or negative result has been confirmed, the results will not change in later sweat tests.  Other diagnostic tools include chest x-Ray, sinus x-Ray, lung function tests and sputum culture.  These tests are more helpful is analyzing the progress of the disorder once a diagnosis has been confirmed.


Sources: National Institutes of Health and Cystic Fibrosis Foundation