Page 41 - HA Convention 2016 [Abstracts (Day 1)]

Masterclasses HOSPITAL AUTHORITY CONVENTION 2016

M7.5 Expanded Newborn Metabolic Screening in Hong Kong: 16:15 Convention Hall A
Collaboration in Implementation

How to Handle Abnormal Newborn Metabolic Screening Results — Causes, Management and Follow-up Tuesday, 3 May
Chong JSC
Department of Paediatrics and Department of Obstetrics and Gynaecology, Faculty of Medicine,
The Chinese University of Hong Kong, Hong Kong

Newborn metabolic screening (NBS) programme aims at early identification of patients with inborn errors of metabolism
(IEM) at a presymptomatic period for early intervention. NBS sampling with dried blood spot cards could be obtained by
collecting a few drops of blood from a baby’s heel prick. A panel of metabolic analytes including amino acids, free carnitine,
acylcarnitines, could be measured by using the method tandem mass spectrometry (MS/MS). Any abnormal or uncertain
newborn metabolic screening result should be followed by assessment of baby, followup and diagnostic testing to determine
disease status.

As a screening test, it should be highly sensitive, but it may not be diagnostics and may not be able to determine the disease
status. Some of the initial abnormal or uncertain screening results will be followed by a normal followup testing. There are
several factors affecting the NBS results including timing of sample collection, sampling method and quality, condition of
baby, feeding type and amount, medications, and maternal conditions. In managing abnormal results, the nature of the
particular IEM condition will provide a good guideline for further investigations and management. Protocol for work up of
different abnormal result should be specific. Diagnostic testing may include free carnitine, acylcarnitine, and amino acid in
blood, urine organic acids profile, genetic testing, and routine biochemical testing subject to baby’s condition. Some of the
IEM conditions may present and deteriorate with acute decompensation within several days after birth. Therefore, apart from
the quality assurance of the newborn screening testing in the laboratory, the logistics pipeline of a newborn screening service
determine the success of programme. Appropriate management should be offered timely, and should be offered before they
develop any signs or symptoms of the diseases, to ensure a better possible outcome, and reduce the morbidity and mortality
resulting from IEM disorders.

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