National Testing Centre

About Us

The National Testing Centre (NTC) screens newborn babies throughout New Zealand for the presence of metabolites indicating the possible presence of a number of congenital conditions. NTC also screens pregnant women for the possibility of having an infant with a chromosome abnormality and other conditions, and symptomatic people for the possibility of having an inborn error of metabolism.

Antenatal screening for Down syndrome and other conditions

Please visit the National Screening Unit website for information - click here to open website in a new window

The new request form can also be accessed via the NSU website - click here to download PDF (112 KB)

Key contacts

• Director Dr Dianne Webster
• Team Leader Mary Stuart
• Technical Specialist Claire de Luen

Fax number: +64 9 307 4936

Quick links to services

• Newborn Baby Metabolic Screening
• Biochemical Genetics and Clinical Metabolic Service
• Maternal Serum Screening

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Newborn Baby Metabolic Screening

For information about the Newborn Metabolic Screening programme please refer to the following website:

Ministry of Health National Screening Unit: About the Newborn Metabolic Screening Programme

Any further questions can be emailed to National Testing Centre

Key contacts

• Director Dr Dianne Webster
• Scientific Officer Detlef Knoll

Biochemical Genetics and Clinical Metabolic Service

This discipline covers the diagnosis and treatment of inborn errors of metabolism or inherited metabolic diseases. Generally due to enzyme deficiencies, these conditions can present in many different ways at any age, although they are most common in infancy and childhood. There are over 400 of these disorders.

Diagnosis involves testing blood (cells or plasma), urine or cultured cells for either metabolites indicative of the disorders or the possibly defective enzymes.

The most common biochemical genetics tests are:

For intermediary metabolite disorders 

• Plasma aminoacids (aminoacid analyser) for aminoacidopathies, for example PKU and cystinuria etc
• Urine organic acids (GC-MS) for disorders like propionic acidemia, methylmalonic acidemia
• Blood acylcarnitines (tandem MS) for fatty acid oxidation disorders, for example MCAD

For storage disorders

• Urine electrophoresis for mucopolysaccharidoses, for example Morquio syndrome

The clinical metabolic service cares for patients with diagnosed metabolic disease.

Key contacts

• Technical Specialist Claire de Luen
• Metabolic Physician Dr Callum Wilson
• Dietician Rhonda Akroyd

Maternal Serum Screening

First trimester or second trimester screen

Maternal serum screening is a screen for Down Syndrome and other conditions.

Principally this involves either a first trimester serum screen combining the nuchal translucency ultrasound measurement with maternal PAPP-A and free beta HCG or a second trimester Screen achieved by performing a blood test measuring AFP, free beta HCG , unconjugated Estriol and Inhibin A. A computer algorithm compares the levels to those found in the affected and unaffected pregnancies and adds the maternal age risk to estimate the overall risk.

A first trimester screen for chromosome abnormalities may be done after 9 completed weeks and before 13 weeks 6 days.

A second trimester screen may be done after 14 weeks and before 20 weeks 6 days.  A screen for neural tube defects will be included in screens done after 15 completed weeks.

The Ministry of Health National Screening Unit website has further information.

The National Screening Unit (NSU) is paying for all first trimester  screens combined  with a nuchal translucency scan measurement to give an overall risk. The NSU is also paying for a second trimester serum screen where a combined nuchal translucency and first trimester screen has not been done. This may be due to late booking or when a nuchal translucency has not been measured for some reason.

The Ministry of Health National Screening Unit website on screening options for antenatal screening for Down syndrome and other conditions has further information.

We provide request forms and patient information sheets with backup telephone explanations whenever required to doctors and midwives wishing to offer this service to their patients. 

Second trimester request forms and information are also available on the Ministry of Health NSU website.

Key contacts

• Director Dr Dianne Webster
• Team Leader Mary Stuart