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Newborn Screening Ontario
Screening Results

Cystic Fibrosis (CF)Download version for offline viewing or printing

At a Glance

Approximate Incidence in Ontario

1 in 3600

Marker Measured

Immunoreactive trypsinogen (IRT), CFTR mutation panel, CFTR gene sequencing

Screening can Prevent

Severe growth failure, severe chronic lung disease, early death


Pulmonary therapy, enzyme replacement

  • Screening is Important
    • In Ontario, a heel prick is used to take a few drops of blood from each baby shortly after birth. The blood is tested for more than 25 treatable diseases, including Cystic Fibrosis (CF).
    • A screen positive result means that there is a high chance a baby could have CF, or develop some of the same health problems that people with CF have when they get older, and more tests are needed to know for sure. Babies identified to have CF at a young age through screening can be treated early. Those babies who might in the future develop some of the same health issues as a person with CF can be monitored to help identify any health problems earlier.
  • What is CF?

    Cystic Fibrosis is an inherited (genetic) disease that causes ongoing health problems.

    CF causes thick mucus to build up in different organs in the body.

    • Mucus in the lungs can cause difficulty breathing and traps bacteria in the airways, leading to inflammation and lung infections.
    • Mucus buildup in the pancreas prevents the release of digestive enzymes and can lead to problems breaking down food and absorbing nutrients.
    • If diagnosed early, medications and other therapies can help children with CF live healthier lives with fewer symptoms.
  • Screening Positive for CF
    • It is natural for parents and guardians to feel worried and have many questions when their baby has a screen positive result.
    • A positive screening result means there is a high chance that your baby could have CF or develop some of the same health issues that people with CF can have, and more testing is needed to know for sure
    • The baby’s health care provider or a health care provider at a Newborn Screening Regional Treatment Centre will discuss the results with the baby’s family.
    • A sweat test will be arranged as quickly as possible for the baby.
    • A sweat test is a painless test that measures the amount of salt in a baby’s sweat. It is one of the best ways to check for CF.
    • It can take a few days to weeks to confirm that a baby has CF. This waiting period can be hard for families.
  • Possible Follow-up Test Results

    Possible sweat test results

    • Abnormal - the baby most likely has CF and the family will be supported by a team of specialists who will ensure that the baby gets the necessary treatment and care.
    • Borderline Results - more testing or follow-up is needed to determine whether a child has CF, or might, when they are older, develop some of the same health issues that people with CF can have.  The family will be supported by a team of health care providers who will ensure that appropriate follow-up takes place.
    • Normal -  the baby is unlikely to have CF. Rarely, a baby can have a normal sweat test and still have CF. Some babies who have a normal sweat test could develop some of the same health issues that people with CF can have when they get older.  A doctor or health care professional who specializes in CF will let the family know if more tests or follow-up are suggested for a baby who has had a normal sweat test.

    Note: Sometimes not enough sweat is collected to get a result from the test. If this happens, the baby will need a follow-up appointment to repeat the sweat test.

  • Signs and Symptoms

    Babies with CF usually have no signs of the disease at birth.

    Common problems in babies with CF can include:

    • Problems gaining weight
    • Meconium ileus or bowel disturbances, such as frequent, oily stools
    • Salty tasting sweat

    Problems that can occur after the newborn period:

    • Breathing problems (such as persistent cough)
    • Problems conceiving children

    Symptoms can range from mild in some people to serious in others. Early treatment helps to prevent serious health problems.

  • Treatment

    Treatment for CF may include:

    • Airway clearance and physiotherapy
    • Pancreatic enzyme supplements to help digest food
    • Vitamins and supplements
    • Medications to help fight or prevent infections, keep the lungs clear, and/or in some cases, to correct the non-working protein made by the CF gene
    • Other treatment as needed


      Babies who have a positive newborn screen for CF and a normal or borderline sweat test may be offered extra check ups to monitor their child’s growth and health.


  • Living with CF
    • Treatment helps children and adults live longer and healthier lives.
    • Even with treatment, children and adults may experience some symptoms of the disease.
    • CF does not affect a child’s development
    • Most children are able to have a very good quality of life by learning to manage the disease.