If
cystic fibrosis is suspected, a genetic test may be
done to confirm the results of an unclear or positive sweat test. This blood
test 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
whether 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.
Genetic counseling is recommended before having a
genetic test.
Some states offer genetic testing for the cystic fibrosis gene. The
National Institutes of Health (NIH) recommend testing 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.
A genetic test for cystic fibrosis also can be done before birth
using
chorionic villus sampling (CVS) or
amniocentesis.