Newborn metabolic screening is a simple and important check that is strongly recommended for all babies. It offers the best possible start to infants born with a number of rare, serious and treatable disorders. Since the New Zealand newborn metabolic screening programme began in 1969, over 1,800 babies have been given the best start in life by having their serious condition detected by newborn screening. Many of these babies are now parents and grandparents themselves.
The screening involves a small blood sample collected from a baby’s heel onto a bloodspot card, which is then sent to the screening laboratory for testing. Early diagnosis through screening means that treatment can start quickly, before the baby becomes sick. Around 40–50 affected infants are picked up each year.
Screening identifies over 25 disorders
There are over 25 individual disorders that can be identified through screening, including congenital hypothyroidism, congenital adrenal hyperplasia, cystic fibrosis, amino acid breakdown disorders (including phenylketonuria), fatty acid oxidation disorders, galactosaemia, biotinidase deficiency and severe combined immune deficiency (SCID).
These disorders are hard to find without screening as there is usually no sign of disease before the screen result comes back. Although these disorders can’t be cured, early treatment such as medication or a special diet can help babies to stay well and prevent severe disability or even death.
The most common disorder
Congenital hypothyroidism is the most common disorder detected, with about 30 affected babies picked up in New Zealand each year. The thyroid gland is critical for normal growth and brain development. Babies with untreated congenital hypothyroidism appear normal at birth but, untreated, would go on to develop intellectual impairment over the first years of life. Treatment with a daily replacement dose of thyroxine allows affected children to reach their full potential.
Helping babies with SCID
Babies with SCID are born with little or no immune system. Although affected babies appear healthy at birth, they typically suffer from a series of life-threatening infections over the first few months of life. The screening programme started screening for SCID in December 2017 and expects to pick up one affected infant each year. Early detection through screening means that these babies can be treated with a stem cell transplant before they become unwell.
Recommended by health professionals
The newborn metabolic screening test is strongly recommended by health professionals and the Ministry of Health. The screening test is discussed with pregnant women by their lead maternity carer (LMC) and babies screened with the consent of their parents. Cards are usually stored by the screening programme but can also be returned at the request of families.
It is important to understand the limitations of newborn screening. If there are concerns about a baby’s health or development the family doctor should still be consulted for a comprehensive assessment, regardless of the newborn screen result. While screening identifies almost all babies with the disorder tested for, sometimes screening may not pick up a condition, or an infant could have a disorder that is not part of the routine screen.
During pregnancy, parents should talk to their LMC about family members with inherited disease. This is because routine screening may not be the best way to look for these conditions.
The programme is overseen by the National Screening Unit, Ministry of Health.