Prenatal Screening
If you're pregnant, prenatal genetic tests can show whether your fetus has CF. These tests include amniocentesis where the doctor can insert a hollow needle through the abdominal wall into the uterus, and then remove a small amount of fluid from the sac around the baby. Then the fluid will be tested to see whether both of the babies cystic fibrosis transmembrane conductance regulator (CFTR) genes are normal. Another prenatal test is the chorionic villus sampling (CVS) where the physician threads a thin tube through the vagina and cervix to the placenta, and removes a tissue sample from the placenta using some gentle suction, and then the sample is tested for cystic fibrosis.
- All States screen newborns for CF using a genetic test or a blood test. The genetic test shows whether a newborn has faulty CFTR genes. The blood test shows whether a newborn's pancreas is working properly.
Sweat TestA sweat test measures the amount of salt in sweat.
For this test, the doctor triggers sweating on a small patch of skin on an arm or leg. He or she rubs the skin with a sweat-producing chemical and then uses an electrode to provide a mild electrical current. This may cause a tingling or warm feeling.
Sweat is collected on a pad or paper and then analyzed. The sweat test usually is done twice. High salt levels confirm a diagnosis of CF.
Chest Xray
A chest x ray can show whether your lungs are inflamed or scarred, or whether they trap air. Frontal chest x-ray in cystic fibrosis can show diffuse interstitial disease with bronchiectasis and nodular densities of mucoid impaction.Lung function tests
- Spirometry. This test measures how much air you can breathe in and out. It also measures how fast you can blow air out.
- Lung volume measurement. This test, in addition to spirometry, measures how much air remains in your lungs after you breathe out fully.
- Lung diffusion capacity. This test measures how well oxygen passes from your lungs to your bloodstream.
