Newborn screening

Page content: Introduction | Conducting the test | Timing of the test | Test results for metabolic conditions | Test results for cystic fibrosis | Screening liaison person | Informing parents about the tests | Consent | Storage of cards | Contacts | Download document

Guidelines for Newborn Screening November 2001

Introduction

Newborn screening tests have been available to all babies in Victoria for the last 30 years. These screening tests ensure the early detection and treatment of a number of rare but important conditions. Among the 62,000 babies born each year in Victoria, about 45 are diagnosed with one of these serious conditions. For several decades babies have been screened for phenylketonuria, congenital hypothyroidism and cystic fibrosis. Following the introduction of tandem mass spectrometry (TMS), the pattern of biochemical markers may help identify over 20 additional metabolic conditions, for example, Medium Chain Acyl Coenzyme A (MCAD) deficiency, homocystinuria and maple syrup urine disease. TMS will enable about 9 babies with one of these conditions to be detected each year. Early detection enables earlier treatment, resulting in reduced risk of severe and sometimes fatal illness and a better outcome for those babies.

MCAD deficiency is the most common fatty acid oxidation disorder and is caused by deficiency of an enzyme that breaks down fat to give energy. Problems occur when babies have viral infections or periods of fasting. If not treated, MCAD deficiency can be fatal - data from North Carolina show that up to one quarter of affected babies die during their first episode of illness. Treatment is effective and focuses on preventing long periods of fasting.

Homocystinuria is caused by an enzyme deficiency resulting in an inability to break down the amino acid methionine. Without treatment homocystinuria can cause thrombosis in arteries and veins, dislocation of lenses in the eyes, mild to moderate intellectual disability and osteoporosis. Treatment involves high doses of Vitamin B6 or a low protein diet with supplements of the essential amino acids except methionine.

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Conducting the test

The newborn screening test is carried out on a blood sample obtained by a heel prick, placed on special pre-printed filter paper (Guthrie cards), and processed at the Newborn Screening Laboratory of Genetic Health Services Victoria (Genetic Health), located at The Royal Children's Hospital. It is essential to complete all of the information on the Guthrie cards. Genetic Health will issue educational kits to maternity units on procedures for collecting, handling and forwarding newborn screening samples. Genetic Health staff will be available to answer questions and provide education to other health professionals about the program.

Timing of the test

It is recommended that the newborn screening test be performed when the baby is between 48 and 72 hours of age. False positives and negatives can sometimes occur when the screening tests are done before 48 hours. The period of hospitalisation provides the only certain opportunity for testing. If the baby is discharged before 48 hours, the test must be carried out before the baby leaves hospital, and then again in the community as soon after 48 hours as possible. Guthrie cards should be sent daily to the Newborn Screening Laboratory, after air-drying.

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Test results for metabolic conditions

Initial test results are normally available 24 hours after the sample is received in the laboratory.

Urgent follow-up:

Parents of babies whose test results are clearly indicative of any of the disorders will be notified by telephone, and confirmatory testing organised. Additional notification will be made to the paediatrician/doctor or hospital shown on the newborn screening test, wherever possible.

Retesting:

Retesting is carried out in the following circumstances:

• Insufficient/contaminated test samples (the laboratory will make a written request for resample)
• Borderline results, which are likely to be of a transient nature but require confirmation (the laboratory will make a phone request for resample)
• When blood is collected before 48 hours, it is expected the referring hospital/agent will automatically send another sample collected between 48 and 72 hours.

Test results for Cystic Fibrosis (CF)

Newborn screening for CF involves several different tests and it takes between 4 to 6 weeks to get the initial results. There are 3 possible outcomes for babies: very low risk, increased risk and affected. Parents/guardians of babies who are at increased risk or affected with CF are referred to a genetic counsellor for appropriate follow up and management. Follow up of babies occurs at Genetic Health located at the Royal Children's Hospital.

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Hospital nominated newborn screening liaison person

Hospitals should ensure that a nominated person eg. community liaison midwife or unit manager of maternity, is responsible for handling telephone calls, correspondence concerning newborn screening and the organisation of retesting.

Responsibilities of the nominated newborn screening liaison person:

• Acting as the contact for the Newborn Screening Program in the hospital/unit
• Checking the quality of blood samples and data on cards to be sent daily by post or courier
• Contacting the parents when a resample is necessary and giving them the request to resample provided by the laboratory
• Ensuring that the newborn screening report is checked against the hospital births as soon as possible
• Ensuring that the parents receive the newborn screening pamphlets at an appropriate time

The laboratory issues newborn screening reports to all hospitals every week. These reports contain the screening test results for babies for whom samples were received during the previous week. The nominated person should contact the laboratory concerning any baby whose name is missing from the list and check if the sample has been received. If a baby has not had a sample collected the nominated person is responsible for arranging a sample collection. The hospital of birth is responsible for ensuring all babies are offered the newborn screening test. This includes babies who are transferred to other hospitals or domiciliary midwifery programs.

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Informing parents about the screening tests

Before the newborn screening test is performed, staff must ensure that parents or guardians are properly informed about the test and its importance. This information is summarised in the pamphlet 'Newborn Screening Program' and staff should discuss this with parents before the test is performed. The pamphlets should be given to all mothers prior to delivery and the pamphlet also needs to be available for review after their baby's birth. Pamphlets are supplied to maternity units by the newborn screening laboratory and are available in community languages.

Consent

Staff need to obtain verbal consent from parents or guardians before performing the test. There should be documentation on the mother's/ baby's file stating that there has been discussion about the newborn screening test. The file should also show a record of completion of the test.

If parents wish to refuse the test on behalf of their baby, they should be referred to a newborn screening counsellor at Genetic Health for urgent discussion. Any parents refusing the test will need to sign a written statement showing that they understand the potential risk to the healthy development of their baby. The expanded program will diagnose babies for whom urgent treatment may be life saving. Refusals must be documented and signed in the mother's/ baby's file. A newborn screening sample card should be completed with refusal written on it, and sent to the laboratory.

Storage of cards

The Guthrie cards are securely stored in compliance with government regulations at Genetic Health Services Victoria.

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Contacts

Newborn Screening Laboratory

PO Box 1100
Parkville Vic 3052

Enquiries:
Email:screeninglab@murdoch.rch.unimelb.edu.au
Tel (61 3) 8341 6272
Fax (61 3) 8341 6389

Genetic Health Services Victoria

10th Floor
Royal Children's Hospital
Flemington Road
Parkville Vic 3052

Enquiries:
Tel (61 3) 8341 6201
Fax (61 3) 8341 6390
Web site: www.genetichealthvic.net.au (external link)