Newborn screening for Cystic Fibrosis was initiated in Idaho in the fall of 2007 and since then has allowed for early diagnosis of many infants in this state. These infants are currently being managed in Cystic Fibrosis Foundation accredited Centers, and have had the advantage of new nutritional and respiratory treatments instituted at this very critical early age.
Explanation of How the Testing is Done
The primary care practitioner is the first link in identifying these infants. The initial screening test is done by putting four drops of blood on a special card. This blood is tested for several disorders. The test for CF on this card is immunoreactive trypsinogen (IRT). If this test is positive, a second test is performed. If this second test is positive, then the primary care physician orders a sweat chloride test, which should be done at a CFF accredited lab for sweat chloride testing, such as St. Luke’s in Boise, Primary Children’s Hospital in Salt Lake City, or Deaconess Hospital in Spokane. If the sweat chloride test is positive, then the patient is referred to a CFF accredited CF Center.
Newborn Screening May Not Identify Everyone with CF
It is important to remember NBS is just that- screening, and may not identify all infants with cystic fibrosis. It is well recognized that false negative screens may occur in infants with meconium ileus or plug and therefore close observation or further testing may be warranted in these infants. Primary care providers should continue to send patients with clinically significant signs and symptoms of possible CF for more definitive testing such as sweat chloride testing by pilocarpine iontophoresis or to a CFF accredited Center regardless of a negative test in the newborn period.