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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 analysis

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.
    • A screen positive result means that more tests are needed to know whether or not a baby has Cystic Fibrosis. It does not mean that a baby has Cystic Fibrosis. Babies identified at a young age through screening can be treated early to help prevent health problems.
  • What is CF?

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

    Cystic Fibrosis causes a 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 Cystic Fibrosis live healthier lives with fewer symptoms.

  • Screening Positive for CF
    • It is normal for parents and guardians to feel worried when their baby has a screen positive result.
    • Follow-up testing is important to find out whether the baby truly has Cystic Fibrosis.
    • 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.
    • Follow-up tests (a sweat test and sometimes a blood test) are arranged as quickly as possible.
    • A sweat test is a painless test that measures the amount of salt in a baby’s sweat.
    • It can take a few days to weeks to confirm that a baby has Cystic Fibrosis. This waiting period can be hard for families.
  • Possible Follow-up Test Results

    Possible sweat test results

    • Normal -  the baby is unlikely to have Cystic Fibrosis.
    • Abnormal - the baby has Cystic Fibrosis and the family will be supported by a team of caring specialists who will ensure that the baby gets the best care possible.
    • Borderline Results - the baby may or may not have a mild form of Cystic Fibrosis. The family will be supported by a specialist who will ensure that appropriate follow-up takes place.

    Note. Sometimes there is an insufficient amount of sweat to test. In this circumstance, the baby will need a follow-up appointment to repeat the sweat test.

    Sometimes, newborn screening identifies babies who do not have CF, but are carriers for the disease. This happens when a baby is screen positive for CF with only one mutation identified AND has a normal sweat. If your baby was identified to be a CF carrier, please click here for more information.

  • Signs and Symptoms

    Babies with Cystic Fibrosis 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 may include:

    • Medications to help fight infection
    • Airway clearance and physiotherapy
    • Pancreatic enzyme supplements to help digest food
    • Vitamins and supplements
    • Other treatment as needed
  • 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.
    • Cystic Fibrosis does not affect intelligence.
    • Most children are able to have a very good quality of life by learning to manage the disease.