3.+Diagnosis

Newborn Screening Test
Many states now routinely screen newborns for cystic fibrosis. This test checks a sample of the baby's blood to see if his immunoreactive trypsinogen levels are elevated. Elevated immunoreactive trypsinogen is sometimes a warning sign that a person has CF. However, this test is infamous for producing false positives, especially soon after a child's birth. If a newborn tests positive, he will have to be tested again in a few weeks to ensure the correctness of the diagnosis.

Sweat Test
The sweat test is actually the easiest and most accurate test for cystic fibrosis. It would be necessary to confirm a diagnosis of CF. During this test, the chemical pilocarpine is applied to an area of the patients skin. This chemical is then driven into the body with a weak and painless current of electricity. This causes the patient to sweat. The sweat is then collected on a piece of filter paper. If it comes back that the sweat is one-and-a-half to two times saltier than most other people's, the patient almost-surely has cystic fibrosis.

media type="youtube" key="8UCWoz6gUp8?fs=1" height="292" width="359"
The above video gives information on cystic fibrosis and shows the sweat test being performed. It was created by the wonderful Cystic Fibrosis Foundation (see @http://www.cff.org/).

Genetic Testing
If the sweat test doesn't provide a clear-cut answer, then genetic testing may be needed. In this procedure, blood or saliva is taken from the patient. The DNA from the bodily fluid is tested for mutations that cause CF. However, there are at least 1,500 different mutations that cause cystic fibrosis; it is not possible to test for each of them. Because of this, a negative result on a genetic test does not rule out CF.