Newborn Screening Tests

Newborn screening helps doctors find disease in its early stages. Usually, the screen is done 24 to 72 hours (1 to 3 days) after your baby is born.

Most disorders found by newborn screening are treatable. Screening for a disorder in its early stages is important so that doctors can start treatment right away. They can also start to closely monitor your child.

Screening is not the same everywhere

Which disorders your baby is tested for will depend on the country, province, or state you live in. Talk to your health care provider about what disorders newborns are screened for in your area.

Most newborns in developed countries are screened for multiple diseases. In Ontario, all newborns are screened to test for treatable disorders.

What happens during the newborn screening test?

A small blood sample is taken from your baby’s heel. This sample is sent to the Newborn Screening Ontario Program and lab to test for several different disorders and diseases.

Different types of conditions

Newborn screening tests can show whether a baby is at high or low risk for many different disorders. There are four main kinds of disorders:

  • Metabolic diseases: These affect how well the body can break down substances such as fats, sugars, and proteins. If not properly broken down, these substances can build up in the body and cause serious problems.
  • Endocrine disorders: These affect how well the body can make and control hormones. If a child’s hormones are out of balance, his body cannot function or develop properly.
  • Blood disorders: If a child has a blood disorder, the body has a hard time producing a protein inside red blood cells. This protein is called hemoglobin. It helps our body carry oxygen and iron. Not having enough hemoglobin causes medical problems such as anemia.
  • Cystic fibrosis: This disease causes the body to produce abnormally thick mucus. Mucus usually builds up inside the lungs and digestive system. This causes lung infections and problems absorbing important nutrients.

In addition, doctors also check your baby’s hearing.

Screening tests show if your baby is high or low risk

Your newborn’s test results help doctors decide whether to run more tests on your baby.

If the results come back negative, it is very unlikely your baby has any of the conditions.

If a screening test shows a problem, it is called a “positive” test result. This does not mean that your baby has a condition. It means that your baby has a high risk for that disorder. To confirm, doctors need to do further tests.

Your baby's treatment can start right away

If this second test confirms the baby has a problem, something can often be done to help. Treatment can often improve a child’s situation both right away and in the longer term. Getting treatment as early as possible will also help your child.

In Ontario, your closest treatment centre arranges follow-up testing for your baby. Your newborn’s screening team in the treatment centre also helps with:

  • diagnosing your child’s condition
  • treatment
  • managing your child’s condition

Detailed information about each of the conditions screened for in the province of Ontario, Canada, can be found at:

Key points

  • Newborn screening is done in the first few days after birth.
  • Newborn screening uses one blood sample to test for several or many disorders.
  • The screening process only shows if a baby has a high or low risk for a particular disorder.
  • If a test result is positive, another test will be done to confirm whether or not the baby has the disorder.
  • Most disorders found by newborn screening are treatable. Screening for a disorder in its early stages is important so that doctors can start treatment right away.
Andreas Schluze MD, PhD, FRCPC

Watson, Michael S. PhD; Lloyd-Puryear, Michele A. MD, PhD; Mann, Marie Y. MD, MPH; Rinaldo, Piero MD, PhD; Howell, R Rodney MD, editors. Genetics in Medicine. Newborn Screening: Toward a Uniform Screening Panel and System. 8(5) (Supplement):12S-252S, May 2006.