1. Standard Sweat Test
You can have a doctor test your newborn to determine the concentration of sodium and chloride in your baby's sweat. This is the most commonly used screening procedure, and your doctor may recommend waiting until your baby is a few months old before using it. Some newborns don't produce an adequate amount of sweat to provide a reliable sample.
Two samples are gathered by using electrodes to trigger sweat production, and salt levels that are abnormally high confirm the presence of cystic fibrosis (CF).
2. Tests for Couples Trying to Conceive
Both you and your partner can have genetic tests performed to determine whether either of you carries the gene that causes cystic fibrosis. When it was first developed, the test was typically made available only to people who were considered to be at high risk for passing CF on to their children, but it's now available to anyone who wants to use it.
The test will draw saliva samples and blood samples from both of you, and a lab technician will perform a genetic analysis. However, the test doesn't necessarily catch each and every possible CF gene mutation, so it's not 100 percent accurate.
3. Genetic CF Tests
Prenatal genetic tests can also be used to determine if your unborn child has cystic fibrosis. The mother's amniotic fluid or placental fluid is tested to see if traces of the CF gene are present. While your doctor won't be able to do anything to treat CF until the baby is born, prenatal screenings allow parents to make informed plans about the future and prepare for challenges ahead of time.
4. IRT and BABI Tests
Your doctor might order an immunoreactive trypsinogen test (IRT) on your baby as part of a cystic fibrosis screening procedure. This test is used only if your baby shows symptoms of cystic fibrosis or does not produce any solid waste within the first 48 hours of life. It's far from foolproof, so additional tests must usually be performed if the lab reaches a suspicious result. However, it continues to be used because it's easy, inexpensive and noninvasive.
BABI is short for "blastomere analysis before implantation." While this test is still in its developmental stages, it shows promise for being able to predict CF and a range of other diseases via test-tube analysis of male sperm and a female egg.
5. Physical Examination Follow-Ups
If your baby shows signs of cystic fibrosis, your doctor may elect to perform lung, liver and pancreas function tests and take chest X-rays to determine if any physical signs of CF are present. However, these procedures are always used in combination with other techniques, because they cannot provide a definitive diagnosis on their own.
