Reproductive Medicine
Newborn Metabolic Screening Program
Every parent anticipates the birth of a healthy baby. However, about 1 in 4.,000 newborns may have an ‘Inborn Errors of Metabolism’ (IEM), or other serious genetic conditions, such as Cystic Fibrosis (CF), Spinal Muscular Atrophy (SMA) or Severe Combined Immunodeficiency (SCID), which, if left undetected and untreated, could significantly affect long term health and development of the child. Since 2013, The Chinese University of Hong Kong (CUHK) has offered an expanded newborn screening program that enables early detection of a wide range of metabolic diseases and other genetic conditions that were previously not tested for in Hong Kong.
Latest Update July 2026
- More than 124,321 babies had been screened in Newborn Metabolic Screening Programme since July 2013.
- Our Newborn Screening Programme covers metabolic diseases (inborn errors of metabolism), genetic conditions of spinal muscular atrophy (SMA), severe combined immunodeficiency (SCID) and cystic fibrosis.
- From November 2017 onwards, we accept all newborn babies including preterm babies, to join the newborn metabolic screening programme.
- In September 2021, screening for X-linked adrenoleukodystrophy (X-ALD) has been added to the IEM panel, therefore the panel is screening for a total of 31 IEM disorders. The aim is to identify affected infants at the earliest instance, often before they develop any signs or symptoms of the disease and treat them as early as possible so as to achieve a better treatment outcome.
In addition, screening for spinal muscular atrophy (SMA) and severe combined immunodeficiency (SCID) have also been included in the program in September 2021 to identify the affected patients soon after birth and offer treatment earlier to achieve a better outcome in infants with SMA and SCID.
- From 1 December 2025, there are three new IEMs added to the NBS screening panel, including Galactosemia, Mucopolysaccharidosis 1 and Biotinidase Deficiency.
- Pamphlet of the newborn metabolic screening (IEM) revised
- Pamphlet of the biotinidase deficiency
- Pamphlet of the galactosemia
- Pamphlet of the Mucopolysaccharidosis type I (MPS I)
- From April, 2026, there are two new single panels including Mucopolysaccharidosis type (MPS1) and Cystic Fibrosis (CF).
- Pamphlet of the Mucopolysaccharidosis type I (MPS I)
- Pamphlet of Cystic Fibrosis (CF)
- Newborn Metabolic Screening Program Clinical Protocol
- Brief Report
Babies with inborn errors of metabolism, spinal muscular atrophy (SMA), severe combined immunodeficiency (SCID) or related disorders would follow up at the Paediatric Metabolic Clinic.
For interested parents, please contact us at 5600 1970 during office hours within 7 days after baby is delivered.
For referring centre, please call (852) 6806 4590 or
email pdc‑obg@mailserv.med.cuhk.edu.hk to request collection cards and forms
What is Inborn Errors of Metabolism?
IEMs are genetic defects which prevent some essential enzymes in the body from being produced. As a result, there is deficiency of certain essential components, or accumulation of toxic substances in the body. If these disorders are untreated, they can lead to serious outcomes including learning difficulties, mental retardation, organ dysfunction and even death. Some of these conditions are however potentially treatable nowadays, with effective screening test performed as early as few days after birth.
What conditions are screened?
The test screens for 37 conditions belonging to the following categories:
- Amino acid disorders
- Fatty acid oxidation disorders
- Organic acid disorders
- Lysosomal Storage Disorders
- Peroxisomal Disorders
- Others
Plus 3 genetic conditions: SMA, SCID and CF
Please note that not all IEMs can be screened.
Who needs to be screened?
Every newborn baby is recommended to be screened unless the baby’s health condition is not suitable.
How to screen for these conditions?
A few drops of blood are collected onto a card by pricking the baby’s heel after completing oral feeding for 1 day, and up to the 7th day of life. Results will be available within a few days.
How accurate is the screening?
The accuracy for the screened conditions is high. Similar to any laboratory screening test, there is a small chance that some affected infants may be missed (false negatives), while some unaffected infants may be wrongly identified (false positives). Therefore, it is extremely important that all abnormal screening results should be followed by standard diagnostic tests for confirmation.
How are results reported?
Results from the screening will be reported as either:
Normal
This indicates that the baby has a very low chance of having one of the 34 IEMs or the additional conditions. The majority of babies (98-99%) will have a normal result.
Positive
This indicates that the baby is at risk of having an IEM or one of the additional conditions. Immediate referral to a Paediatrician for clinical evaluation, further diagnostic workup and management are needed.
Uncertain
This indicates that the sample analysis is inconclusive and a new sample is needed. This may happen in about 1% of all screened babies. Parents of babies with an ‘uncertain result’ will be contacted to arrange for another sample to be taken.
Why do we do it on blood?
| Blood | Urine | |
|---|---|---|
| International gold standard | Yes | No |
| Large worldwide databases of reference ranges and decision cut-offs | Yes | No |
| False positive rate (i.e. re-call rate) | Very low | Uncertain |
| Internationally agreed target diseases | Yes | No |
- We may see slightly abnormal newborn screening results in healthy babies. We call them false positives. Babies with such results have to undergo further confirmatory investigations including blood tests and urine tests to rule out the condition. Therefore false positive results create enormous anxiety to parents.
- Proper selection of target diseases is crucial, because
- Some conditions have onset later in life and are untreatable. Making the diagnosis too early only creates insurance issue and psychological burden to the family.
- Some conditions are very mild and does not require treatment or long-term follow-up.
- Some important IEMs (e.g. carnitine uptake defect) only produce abnormal metabolites in blood.
Enquiries
The CUHK-BCM Joint Centre for Medical Genetics
The Chinese University of Hong Kong
(852) 5600 1970 (office hours)
(852) 3505 4219 (voice mail service available during non-office hours)
