If
cystic fibrosis is suspected, a genetic test may be
done to confirm the results of an unclear or positive
sweat test
. A genetic test is a blood test that detects changes in the genetic
material (DNA) that causes cystic fibrosis.
A
genetic test may also be done to screen people who want to know if they are
likely
carriers of cystic fibrosis, or what their chances are
of having a child who has cystic fibrosis. Anyone who is interested in knowing
his or her status can request the test, but a doctor must order it and the test
is fairly expensive.
Carrier screening is recommended for:1
- Adults who have a positive
family history of cystic fibrosis. They may be a
carrier of the defect in the cystic fibrosis gene.
- Partners of
people who have cystic fibrosis. If the partner also has the defective cystic
fibrosis gene, a child will have a 50% (1-in-2) chance of having cystic
fibrosis.
- Couples who are currently planning to become
pregnant.
- Pregnant women (and their partners) who seek prenatal
care, regardless of family history.
Pregnant women can have a genetic test using
chorionic villus sampling or
amniocentesis. And newborns can have a genetic test
too.
Genetic counseling is recommended
before having a genetic test. For more information, see the topic Genetics or
Genetic Test.