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Ann Clin Biochem. 2014 Mar;51(Pt 2):237-47. doi: 10.1177/0004563213491078. Epub 2013 Jul 30.

Diagnostic applications of newborn screening for α-thalassaemias, haemoglobins E and H disorders using isoelectric focusing on dry blood spots.

Author information

1
Hematology Division, Phramongkutklao Hospital, Bangkok, Thailand.

Abstract

BACKGROUND:

Neonatal screening for haemoglobin (Hb) disorders is a standard of care in several developed countries with the main objective to detect Hb S. Such practice has not been established in Thailand where α-thalassaemia and haemoglobin E (Hb E) are highly prevalent. Early identification of thalassaemias could be helpful and strengthen the programme for prevention and control for severe thalassaemias.

METHODS:

Data from isoelectric focusing (IEF) and Isoscan® for detecting types and amount (%) of each haemoglobin in 350 newborn's dried blood spots were analysed and compared with the comprehensive genotype analysis by DNA studies as a gold standard.

RESULTS:

Based on genetic profiles, there were 10 different categories: (1) normal (n = 227), (2) α(+)-thalassaemia trait (n = 14), (3) α(0)-thalassaemia trait (n = 13), (4) β(0)-thalassaemia trait (n = 7), (5) Hb E trait (n = 72), (6) Hb E trait with α(0)-thalassaemia or homozygous α(+)-thalassaemia (n = 5), (7) Hb E trait with α(+)-thalassaemia trait (n = 5), (8) homozygous Hb E (n = 3), (9) homozygous Hb E with α(0)-thalassaemia trait (n = 1) and (10) Hb H disease (n = 3). The presence of Hb Bart's and Hb E were used to identify cases with α-thalassaemia and Hb E, respectively. We set 0.25% of Hb Bart's and 1.5% of Hb E as a cut-off level to detect α(+)-thalassaemia trait (sensitivity 92.86% and specificity 74.0%) and Hb E trait with 100% of both sensitivity and specificity for IEF diagnosis.

CONCLUSION:

Although molecular diagnosis seems to be better for definitive diagnosis of thalassaemia syndromes at birth, however, using our reference range described herein, IEF can be applied in a resource-limiting setting with acceptable reliability.

KEYWORDS:

AE-Bart’s disease; EF Bart’s disease; haemoglobin E heterozygote; homozygous haemoglobin E; isoelectric focusing; new born screening; α-Thalassaemia

PMID:
23901141
DOI:
10.1177/0004563213491078
[Indexed for MEDLINE]

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