Newborn screening tests are part of a worldwide practice to detect rare but serious health problems (genetic or metabolic disorders) in newborn babies. Early diagnosis of these conditions enables treatment to begin at the earliest opportunity and reduces the ill effects of these disorders throughout life. Free screening of newborn babies has been available in Australia since the late 1960s. Around 99 per cent of babies receive newborn bloodspot screening.
How is newborn bloodspot screening carried out?
You will be offered the newborn bloodspot screening test in hospital (if your baby is born there) or at home. The test is normally done between 48 hours and 72 hours after the birth. If you leave hospital within 48 hours, a midwife may collect your baby’s blood sample later at home.
The bloodspot sample is normally collected by a midwife. It used to be called the ‘heel prick’ test. A few drops of blood are taken from your baby’s heel and collected onto a special card (called a Guthrie card). The card is then sent to a special screening laboratory for testing.
Newborn bloodspot screening tests your baby to see if they have or are at risk of a range of medical conditions (see below). If the test suggests your baby is at risk of having one of the conditions, healthcare providers will contact you and may suggest further tests or treatments that can be started to reduce the impact of the condition.
Newborn screening tests are not compulsory, but if parents don’t allow their baby to be tested they could be risking its health. If a serious condition goes undetected, it can continue to affect your baby’s growth and development, causing disability or even death.
Will the bloodspot screening test hurt my baby?
The heel prick may cause momentary discomfort to your baby. Some mothers like to breastfeed or hold their baby during the test.
What medical conditions are screened for?
For several decades, babies have been screened for phenylketonuria, congenital hypothyroidism, cystic fibrosis and galactosaemia. However, nowadays, around 25 to 30 different disorders are screened for using the bloodspot test, including disorders of fat metabolism, congenital adrenal hyperplasia, maple syrup urine disease, homocystinuria and tyrosinaemia.
Phenylketonuria (known as PKU) is a rare inherited disorder affecting about one in 10,000 babies in Australia. Babies with phenylketonuria are born with a deficiency of the enzyme needed to break down an amino acid called phenylalanine. Without treatment, high levels of phenylalanine accumulate in the blood, resulting in severe brain damage. Detection of phenylketonuria at birth means that babies can be treated with special milk, and eventually a special diet, which allows them to grow and develop normally.
Congenital hypothyroidism affects about one in 3000 to one in 4000 babies in Australia. It occurs when the thyroid gland is absent, is too small, or does not produce enough thyroid hormone. If untreated, it can lead to poor growth and development. Treatment with a daily thyroid hormone tablet allows affected children to grow and develop normally.
Cystic fibrosis occurs in about one in 2500 babies in Australia. It is an inherited condition that causes the body to produce thicker than normal mucus in the lungs and digestive tract. Affected children have problems digesting and absorbing food and are prone to serious chest infections.
The newborn blood screening test determines whether the amount of a digestive enzyme (a chemical produced by the body to help food digestion) is abnormal. Further tests, such as a sweat test, may be needed to confirm a diagnosis of cystic fibrosis.
Early detection, combined with advances in medical treatment, has significantly improved the lives of babies with cystic fibrosis. However, it is rare but possible that not all the genetic changes that cause cystic fibrosis will be picked up on initial testing. Therefore, you should seek medical advice if your baby is failing to gain weight properly, having frequent chest infections or passing frequent bulky, foul-smelling, oily stools.
Galactosaemia is a very rare inherited disorder affecting about one in 50,000 babies in Australia. An affected baby cannot process galactose effectively. Galactose is a naturally occurring sugar found in both breast and cow’s milk. This deficiency leads to an accumulation of galactose in the blood. Serious illness can be prevented when this condition is detected early and babies are given a specially formulated milk. Galactosaemia may not be screened for in the newborn screening programme in Victoria. Check with your healthcare provider if you live in Victoria.
Disorders of fat metabolism (fatty acid oxidation defects)
These disorders are rare and are due to enzymes involved in fat metabolism being defective. They mean your baby may not be able to break down fats in the usual way. Once the disorders are detected, they can usually be treated by modifying the baby’s diet.
When will I get the results of the test?
Parents are not routinely told the results of the newborn bloodspot screening test. You will be contacted only if the test needs to be repeated or your baby’s results aren’t normal, but almost all babies have normal results.
The results are usually returned to your doctor or midwife within 2 weeks. About one in 100 babies needs a second test because the results are inconclusive. Your doctor or midwife will contact you if this is the case. Most second tests give normal results, and your doctor or midwife will be notified accordingly. If the test is positive for any of the conditions being tested, your doctor or midwife or the test centre will contact you to arrange an appointment for further tests or treatment.
What if I don’t want my baby to be tested?
Newborn bloodspot screening is not compulsory in Australia, therefore you have the right to refuse the tests on your baby’s behalf. If you refuse the test you may be asked to discuss the situation with a genetic counsellor and you will be asked to sign a written statement showing that you understand the potential risk to the healthy development of your baby. Remember, if your baby is affected by one of these conditions it may be some time before symptoms show and in the interim their development could be permanently impaired or they may even die.