Your Newborn Baby's Blood Test: The Newborn Metabolic Screening Programme

Your Newborn Baby's Blood Test: The Newborn Metabolic Screening Programme

HE Code: 
HE2310
Language: 
Format: 
Pamphlet A5
Publication date: 
1 November 2010
Status: Hard copies currently out of stock.
An explanation of the newborn metabolic screening test (the Guthrie or heel prick test) and the conditions it can identify, and of parents' right to give informed consent, including choosing whether or not to have leftover blood spots from the blood-spot card returned.

Newborn Screening

Free health checks for your baby

All babies are checked at birth to see that all is well. Some of your baby’s health checks are called ‘screening’.

The Newborn Metabolic Screening Programme

The Newborn Metabolic Screening Programme detects rare but life-threatening metabolic disorders with a blood test done at 48 hours old or as soon as possible after this. Since 1969, almost all babies in New Zealand have had this screening. Early diagnosis means that treatment can start quickly, before the baby becomes sick. Metabolic disorders are hard to find without screening.

Why screen for metabolic disorders?

Screening saves lives. Each year, about 45 New Zealand babies are found to have a metabolic disorder. Although these disorders cannot be cured, early treatment with medication or a special diet can help your baby stay well and prevent severe disability or even death.

Metabolic disorders can occur in any family, even when there is no family history of disorders. Screening is an important way of identifying babies who are more likely than other babies to have a disorder.

Who is newborn metabolic screening for?

Newborn metabolic screening is offered free for babies born in New Zealand. Your midwife or doctor will talk with you during pregnancy about screening for your baby.

The Ministry of Health strongly recommends screening for your baby.

How is the blood sample collected?

The blood sample is collected from your baby’s heel onto a blood spot card. The blood spot card is sent to the laboratory for testing. For the most accurate test results, the sample must be collected when your baby is 48 hours old or as soon as possible after this.

It is your decision to have your baby screened. When your baby has screening, you also need to decide whether the leftover blood spots are stored or returned to you after screening.

Test results

Your midwife or doctor will receive your baby’s results and tell you what they are. This will be within 10 days if the results are negative. If any result is positive, the laboratory will notify your midwife or doctor as soon as possible.

Why is another blood sample sometimes needed?

Another blood sample may need to be taken if the first test result is not clear. If another sample is needed from your baby, your midwife or doctor will tell you why.

It is important that the new sample is taken as soon as possible so that your baby completes screening.

What if my baby has a positive result?

If your baby has a positive screening result, a further sample and/or referral to a specialist may be required. The specialist will examine your baby and order diagnostic testing to confirm whether your baby has a disorder or not. It is important to complete the diagnostic testing as soon as possible so that if your baby has a disorder, treatment can start straight away.

Screening identifies almost all babies who have a disorder. There is a small chance that some babies may be missed or a screening result will be positive for a baby who does not have a disorder.

The newborn metabolic screening process

Flowchart illustrating the metabolic screening process.

(Read a description of this flowchart.)

What if my baby hasn’t been screened?

If your baby is more than three days old and you don’t think he or she has been screened, talk to your midwife or doctor.

Storage and use of leftover blood spots

Any blood left over after screening is either securely stored or returned to you. Blood is stored to assist with maintaining a high-quality screening programme and for other uses.

What can the stored blood spots be used for?

The stored blood spots may be used:

  • for repeat testing. If your baby has a disorder but did not have a positive test result, the blood sample can be tested again to see why this happened.
  • to improve the screening programme, such as by making sure that testing equipment produces accurate results
  • for research approved by an ethics committee
  • to investigate a death or illness in your family.

The stored blood spots will not be used for anything else without written consent from the parents or guardians or from another lawful authority, such as if ordered by a court. More information is available at www.nsu.govt.nz.

How do I get leftover blood spots returned to me?

You can ask your midwife or doctor to arrange for the leftover blood spots to be returned to you by sending a signed request with the blood spot card. Alternatively, leftover blood spots can be requested at any time using the form ‘Return of Newborn Metabolic Screening Samples’ available at www.nsu.govt.nz.

What information is collected and how is it used?

As part of newborn metabolic screening, basic information about your baby is collected and stored. This includes your baby’s name and address, sex, ethnicity and weight, and where and when your baby was born. Your name is also recorded. The programme holds this information securely and confidentially.

The information is used to:

  • interpret screening results
  • make sure that results can be given to your midwife or doctor
  • check that babies have been screened
  • monitor the screening programme.

The Ministry of Health collects information for monitoring and evaluation of the screening programme. Your decisions about screening will be recorded in your maternity and Well Child/Tamariki Ora notes. If you choose not to have your baby screened, you will also be asked if this information can be sent to the screening programme.

What are my rights?

The Code of Health and Disability Services Consumers’ Rights protects your rights. You can read more about these rights at www.hdc.org.nz

The Health Information Privacy Code protects your privacy. You can read about the code at www.privacy.org.nz

What metabolic disorders are babies screened for?

Babies are screened for over 20 treatable disorders. A full list of the disorders is available at www.nsu.govt.nz

Amino acid disorders, eg, phenylketonuria (PKU)
Caused by a missing enzyme. Without these enzymes, amino acids (such as phenylalanine) rise to harmful levels
Can lead to brain damage and life-threatening complications
Treated by special diet
Occurs in about 5 babies every year
Fatty acid oxidation disorders, eg, medium chain acyl-Co A dehydrogenase (MCAD) deficiency
Caused by a missing enzyme. Without these enzymes, the body cannot break down fats to make energy
Can lead to life-threatening complications
Treated by ensuring regular feeding (a special diet is needed in some disorders)
Occurs in about 5 babies every year
Congenital hypothyroidism
Caused by not enough thyroid hormone
Can lead to slowed growth and developmental delay
Treated by Thyroxine
Occurs in about 20 babies every year
Cystic fibrosis (CF)
Caused by a defective gene and its protein product, leading to thick, sticky mucus
Can lead to poor growth, chest infections and shortened life
Treated by high-calorie diet, medicines and physiotherapy to keep the lungs healthy
Occurs in about 8 babies every year
Congenital adrenal hyperplasia (CAH)
Caused by lack of an enzyme in the adrenal gland
Can lead to life-threatening complications
Treated by steroid medication
Occurs in about 3 babies every year
Biotinidase deficiency
Caused by lack of an enzyme, leading to a deficiency of biotin
Can lead to life-threatening complications
Treated by taking vitamin H (biotin)
Occurs in about 1 baby every 3 years   
Galactosaemia
Caused by an enzyme defect that prevents normal use of milk sugar
Can lead to jaundice, cataracts and life-threatening illness
Treated by special diet including replacement of milk-containing foods
Occurs in about 1 baby every 2 years

The Newborn Metabolic Screening Programme is committed to the highest possible standards. To maintain the quality of the programme, disorders screened for are reviewed and the programme is closely monitored. Further details are available at www.nsu.govt.nz

More information

It is important that you have enough information to help you decide about newborn metabolic screening.

If you would like more information:

Your midwife or doctor can provide you with a DVD about newborn metabolic screening, or you can view this at www.nsu.govt.nz

The Newborn Metabolic Screening Programme is overseen by the National Screening Unit of the Ministry of Health.

The newborn metabolic screening process

  • Talk to your lead maternity carer
  • Do you agree to having your baby screened?
    • If not, your decline will be recorded
    • If you do, the screening process will proceed
  • Do you agree to the storage of the leftover blood or want it returned to you?
  • The blood sample will be collected
  • The laboratory tests the blood sample
  • The results will be sent to your LMC:
    • If the lab reports this was an unsuitable sample, another sample will be taken for testing
    • If there is a negative result, no further action is necessary
    • If there is a positive result, another sample will be taken and/or you will be referred to diagnostic testing
  • Once screening is finished, leftover blood spots will either be stored or returned