The disorders tested for
How the test is done
Re-testing
Storage of the tests
Most industrialised countries (including Australia and New Zealand) have government-funded newborn screening tests (NBST) that involve maternity caregivers taking a small sample of blood from newborn babies, usually by pricking their heel. The baby's blood is tested for several rare disorders that usually relate to their body possibly lacking a specific enzyme necessary for metabolism. The NBST used to be known as the Guthrie test, named in the mid 1960's when it only detected phenylketonuria. However, since the late 1970's additional tests for other disorders have been included. (usually done by pricking the baby's heel). The disorders are generally rare and often collectively referred to as metabolic disorders because they relate to a lack of a specific enzyme that is necessary for the body's metabolism.
The NBST is routinely performed around 3 to 5 days of age. The aim is to detect specific disorders so that treatment can commence before an affected baby shows physical signs of illness and perhaps suffer health consequences due to a late diagnosis. Metabolic disorders can be treated by either altering the baby's diet (in most cases the baby is placed on a special formula, stopping breastfeeding if doing so), and/or giving medications, depending on the disorder the baby has.
There are four main metabolic disorders commonly tested for being
cystic fibrosis,
galactosaemia,
congenital hypothyroidism and
phenylketonuria. However, laboratories in some Australian states have extended their testing in recent years to 30 or so other rare metabolic disorders relating to protein and fat metabolism. For example, Congenital Adrenal Hyperplasia and Maple syrup urine disease. The incidence of these other rare disorders is about 1 in 6,000 babies (or 0.00017%).
Updated September 2008