Cystic Fibrosis
Healthcare Professionals Resources - Newborn Screening

Newborn Screening for Cystic Fibrosis - Information for Healthcare Professionals

Ohio has been screening for cystic fibrosis (CF) with its Newborn Screening Program since 2006. Approximately 500 newborns screen positive for CF through this program each year. However, fewer than 10 percent of babies who screen positive actually have CF.

A confirmatory sweat test must be performed on any baby who screens positive on the CF portion of the newborn screening test. Confirmatory testing for CF can cause anxiety for patients and families, but particularly for the parents of asymptomatic newborns. Clinicians need to strike a delicate balance by encouraging parents to pursue appropriate follow up without unduly alarming the family.

FAQ's: My patient had a positive CF newborn screening test

Studies have shown that babies who are diagnosed with CF through newborn screening benefit from better nutritional status than babies whose diagnosis is delayed. While there is as of yet no cure for CF, symptoms are managed to maintain good nutritional status, slow progression of lung damage and improved quality of life.

CF newborn screening also has implications for the parents’ future offspring. Babies who screen positive have at least one parent who is a CF carrier. Parents who are informed of their child’s carrier status may choose to be tested. If both parents are CF carriers, then future pregnancies are at a one in four risk to have CF. Prenatal diagnosis, serial ultrasound, and other management issues can be considered.

While CF is most common in Caucasians, it occurs in all ethnic groups. Currently, sweat testing is a more sensitive test for CF than DNA analysis, especially in non Caucasians, because of the large number of mutations that are not identified with current screening. CF is inherited, but 80 percent of newly diagnosed patients do not have a family history of CF.

For additional information on CF carriers, visit the CF Foundation website: https://www.cff.org/intro-cf#testing-and-genetics

In Ohio, CF newborn screening is a two-tiered process performed on the standard Guthrie card: 1) analysis of immuno-reactive trypsin (IRT); 2) specimens with IRT levels in the top 5 percent are tested for a panel of CF causing gene mutations. When two mutations are identified, it is consistent with a likely diagnosis of CF, and the baby should be referred immediately to an accredited CF care center for diagnostic testing and management. A visit with CF specialists will occur after the test results are available.

More than 2,000 mutations have been identified in the CF gene. This screening includes many, but not all, of them. Babies  with one mutation should be referred to an accredited CF center for follow up sweat testing. Babies with elevated IRT and no mutations will need a repeat IRT or newborn screen at one month of age. If the IRT remains elevated, then a sweat test and discussion with the CF Center is recommended. It is important to remember that a negative newborn screening test does not completely rule out CF; therefore, if this diagnosis is ever suspected, referral to an accredited CF center should be made.

Take the following action for the appropriate test result:

  • If the sweat test is negative, the baby should continue to receive routine pediatric care.
  • If the sweat test is positive, the baby should have a second sweat test to confirm the diagnosis and then be seen at an accredited CF care center.
  • If the sweat test is borderline, the baby should have a repeat sweat test and genetic mutation analysis.
  • If the sweat test is QNS, a repeat sweat test is indicated when the baby is bigger, usually in about two weeks.

Any baby who has a positive CF newborn screening result should be referred for a sweat test, even if the parents had prenatal CF carrier testing.

  • When informing parents that the results of their baby’s CF test indicate the need for follow up sweat testing, reassure them that most babies who "screen positive" do not actually have the condition.
  • Helpful information for families can be found on the Cincinnati Children's CF Center website.
  • Instruct patients not to use any lotions or creams on the baby’s skin the 24 hours before the sweat test (including moisturizing soaps).
  • Continue the regular feeding schedule of the baby to ensure the baby is well hydrated for the test.
  • Instruct the parents to dress the baby in warm clothing to increase the likelihood of producing enough sweat for a valid test
  • A sweat test will be scheduled once the baby is a month old.  Our newborn screen coordinator will contact you and will then arrange the test as well as genetic counseling.  You do not need to schedule a visit with a pulmonologist at this point.
  • Sweat test results will be called to your office the day of the test. Patients will be instructed that they will be notified of the result by the genetic counselor at Cincinnati Children’s Hospital. 
  • Many parents want to know what symptoms they could see if their baby has CF. Most commonly, babies with CF have difficulty growing or need to consume extra calories to grow. They can also show signs of malabsorption of fat protein from the breast milk or formula. There would be steatorrhea (fatty stools), or frequent, large, foul smelling stools.

Reviewing this information with the family may be overwhelming. Here are some tips and tricks for discussing screening results with parents and families:

  • Whenever possible, do not call families on Fridays. This can lead to unnecessary stress and anxiety for the family as they have to wait until Monday to get scheduled for the sweat test. However, if the baby has two mutations and shows signs of CF, please call the Cincinnati Children's CF Center as soon as possible.
  • Families have told us they want accurate information, emotional support, and steps for what to expect next.
  • If a family is noticeably anxious or worried about the result, suggest some of these stress reduction resources:
  • Let the family know that they can go to the Cincinnati Children's CF Center Website, the CF Foundation Website or can contact the Newborn Screen Coordinator for additional information.

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