generally have higher salt concentrations in their sweat than children. Also,
sweat test results in adults can vary widely. This is especially true in women,
because the amount of salt in their sweat can vary with the phase of their
menstrual cycle. Enough sweat must be collected to get
accurate test results.
If results of a sweat test are positive or
unclear (especially in babies), a blood test may be done to detect changes in
the genetic material (DNA) that causes cystic fibrosis. Blood
test results are usually ready in 10 to 21 days. To learn more, see the
Sweat tests should be done
at labs that are certified by the Cystic Fibrosis Foundation (www.cff.org). These labs
perform a large number of sweat tests and are skilled at sweat test techniques
Farrell PM, et al. (2008). Guidelines for diagnosis of
cystic fibrosis in newborns through older adults: Cystic Fibrosis Foundation
consensus report. Journal of Pediatrics, 153(2):
Other Works Consulted
Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
LeGrys VA, et al. (2007). Diagnostic sweat testing:
The Cystic Fibrosis Foundation Guidelines. Journal of Pediatrics, 151(1): 85–89.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.