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Newborn Screening for Cystic Fibrosis

Newborn screening is a national, public health service that reaches over 4 million babies a year. Newborns are screened for serious health conditions with which they are born. This is done so that these babies can receive treatment early. Newborn screening is available for more than 60 disorders. The specific tests done vary by state, and are decided by each state’s public health department.   As of 2010, Cystic Fibrosis (CF) is one of the newborn screening tests in all 50 states and the District of Columbia. 

The first CF screening test is done a day or two after the baby’s birth with other newborn screening tests.  A few drops of blood are taken from the baby’s heel and placed on a card for testing. If this test comes back positive for CF, further tests are done.  These tests may be different from state-to-state. 

For all states, a sweat test is the main test to diagnose cystic fibrosis. The sweat test measures the amount of salt in sweat.  Babies with CF have too much salt in their sweat.  The sweat test should be test done at a specialized CF Care Center.   The Cystic Fibrosis Foundation (CFF) accredits centers nationwide.  You can find a center near you on the CFF website:  Find a CF Care Center.

If the results of the screening blood test are positive, a sweat test is the next step to determine if a baby has CF. During the test, areas on the newborn’s arms and legs will be stimulated so that they sweat. The sweat is collected on a gauze strip and sent to a lab to be tested.  The test will be either negative (baby does not have CF), positive (baby has CF and will be evaluated by doctors at the CF Care Center), or rarely, intermediate (more testing is required).  Rarely, there is not enough sweat collected and the sweat test must be repeated.

 In Ohio, families will also meet with a genetic counselor on the day of the sweat test to help explain the results of the newborn screen test.

For further information on newborn screening and what to expect from the sweat test, you can visit the CFF website.

What is Cystic Fibrosis?

Cystic fibrosis is a genetic disease. It is inherited if both parents carry a cystic fibrosis (CF) gene and pass it down to their child. However, not all parents with the CF gene will have children with cystic fibrosis. If both parents carry the gene, their child has a 1 in 4 chance of having cystic fibrosis.

CF occurs in 1 in 4,000 U.S. births. It is life threatening. The body makes thick, sticky mucus that can clog lung airways and affect the pancreas, preventing the pancreas from doing its job in digestion. The sweat glands are also affected, so they make very salty sweat.

Why do we test newborns for Cystic Fibrosis?

We test for CF because it is life threatening, and the earlier it is detected, the earlier people can take action to prevent complications and health damage. Only 30 years ago, cystic fibrosis was often fatal before age 20. However, things are better today. Thanks to newborn testing, it can be detected very early, leading to fewer complications and improved life quality for those affected by it.

What if my baby tests positive for Cystic Fibrosis?

Throughout the country there is growing support for cystic fibrosis.  It is important to contact a specialized CF care center where you will find a team of providers to help your child receive the most up-to-date care.  Every day, researchers are learning more about CF and these accredited centers will be sure that you have the best information and care for your child.  For more about CF newborn screening, what it means and what you can do visit the Cystic Fibrosis Foundation.


This children’s health content is brought to you with support from University Hospitals Rainbow Babies & Children’s Hospital.

For more information:

Go to the Cystic Fibrosis health topic.