Screening criteria for beta thalassaemia trait in pregnant women.

Rogers, Martha F.; Phelan, Lorraine; Bain, BJ

doi:10.1136/jcp.48.11.1054

Cited by 20 publications

(12 citation statements)

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“…However, the great majority of -thalassaemia-1 and -thalassaemia heterozygotes would have MCV values less than 80 fl (Ghosh et al, 1985;Rogers et al, 1995;Lafferty et al, 1996), leaving mostly the milder cases of single -globin gene deletion carriers misclassified (Lau et al, 1997). Because some of the subjects were referred to our unit for prenatal diagnosis of homozygous -or -thalassaemia, the incidence of -thalassaemia-1 and -thalassaemia heterozygotes in the present series were much higher than that reported previously (Lau et al, 1997).…”

Section: Discussioncontrasting

confidence: 78%

Risk of neural tube defects in the offspring of thalassaemia carriers in Hong Kong Chinese

Lam

Tang

1999

Prenat. Diagn.

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The risk of having an offspring with neural tube defect is negatively correlated with early pregnancy maternal folate levels. Thalassaemia carriers often have subnormal folate levels. We postulate that their offspring may be at increased risk of having neural tube defect. We retrospectively reviewed the records of 1961 Chinese women referred to a tertiary centre for prenatal diagnosis between January 1997 and August 1998. Women with a mean corpuscular volume greater than 80 fl were assumed not to be α‐thalassaemia‐1 or β‐thalassaemia heterozygotes. α‐ and β‐thalassaemia heterozygotes were diagnosed by haemoglobin studies. Of the 1961 women studied, pregnancy outcome was not available in 20 and thalassaemia screening was not available in 109 and these were excluded from the final analysis. Two‐hundred‐and‐six women were α‐thalassaemia‐1 heterozygotes, 102 women were β‐thalassaemia heterozygotes and one woman had HbE disease. Three α‐thalassaemia carriers and one β‐thalassaemia carrier had a pregnancy affected by anencephaly (odds=1:76). In the 1523 non‐carriers, five pregnancies were affected by spina bifida (odds=1:304). The odds ratio (95 per cent confidence interval) for neural tube defects in the α‐ and β‐thalassaemia carriers was 3.99 (1.07 to 14.94; p<0.05, Chi‐square test). Because of the small number of affected pregnancies studied, the finding needs to be substantiated by a larger series. If the increased risk is genuine, women need to be screened for thalassaemia before conception and the thalassaemia carriers should be given periconceptional folate supplement to reduce the occurrence of neural tube defects. Copyright © 1999 John Wiley & Sons, Ltd.

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Section: Discussioncontrasting

confidence: 78%

Risk of neural tube defects in the offspring of thalassaemia carriers in Hong Kong Chinese

Lam

Tang

1999

Prenat. Diagn.

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“…It is impossible to detect all subjects with ␤ -TT by screening on the basis of the full blood count alone, as some subjects have normal red cell indices (silent ␤ -TT) [13] . Most laboratories use MCV and MCH for screening, but the specifi c cut-off under which further investigation is carried out varies widely [13] .…”

Section: Discussionmentioning

confidence: 99%

“…Most laboratories use MCV and MCH for screening, but the specifi c cut-off under which further investigation is carried out varies widely [13] . Older studies quote a MCH !…”

Section: Discussionmentioning

confidence: 99%

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Screening for β-Thalassaemia Trait in Anaemic Pregnant Women

Benčaiová

Burkhardt²,

Krafft³

et al. 2006

Gynecol Obstet Invest

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Aims: To find a clinically practicable parameter for the identification of β-thalassaemia trait (β-TT) in anaemic pregnant women on the basis of routine use of haematological examination. Methods: During 1998–2002, 304 anaemic pregnant women were observed in anaemia consultation hours. A retrospective study was carried out with the aim of finding a screening method for β-TT in anaemic pregnant women. We compared a sensitivity and a specificity of six different parameters for identification of β-TT. On the basis of a sensitivity and a specificity for each parameter, we calculated Youden’s index, the likelihood ratio and determined the receiver-operating curves. The logistic regression of the variables MCV, MCH and microcytosis was accomplished. Results: The analysis using receiver-operating curves as well as a calculation of Youden’s index showed that the best parameter for screening of β-TT in anaemic pregnant women is MCV ≤75 fl. For differentiation between patients with iron deficiency anaemia (IDA) alone and patients with β-TT and concomitant IDA, microcytosis ≥15% was the most sensitive. By using MCH we identified 100% of patients in the group with β-TT but only 67% of patients in the group with IDA. Conclusion: Our results suggest identification of β-thalassaemia on the basis of quantification of HbA₂ in all patients with MCV ≤75 fl and normal iron status.

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“…If a woman is already pregnant, testing should be done regardless of apparent iron deficiency since a diagnosis of iron deficiency does not exclude coexisting b-thalassaemia. When screening is based on red cell indices, all women with an MCH <27 pg (Rogers et al, 1995) should have further tests performed. The screening of all women necessitates the use of a less labour-intensive technique such as HPLC whereas selective screening can be carried out by either cellulose acetate electrophoresis and microcolumn chromatography or by HPLC.…”

Section: B-thalassaemia Traitmentioning

confidence: 99%

The Laboratory Diagnosis of Haemoglobinopathies

1998

Br J Haematol

122

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The laboratory diagnosis of haemoglobinopathies, including the thalassaemias, is of growing importance, particularly because of an increasing requirement for antenatal diagnosis of significant disorders of globin chain synthesis. This guideline discusses the laboratory tests which are most useful in the diagnosis of haemoglobinopathies and describes their role in specific clinical circumstances. Of the newer technical methods, high‐performance liquid chromatography (HPLC) is of considerable importance whereas isoelectric focusing (IEF) and immunoassay for variant haemoglobins have a more minor role. Specific recommendations have been formulated for testing in relation to genetic counselling and for neonatal diagnosis. Methods used in specialized laboratories for fetal diagnosis have been tabulated. Genetic counselling requires: (i) identification of haemoglobins S, C, D‐Punjab, O‐Arab, E, Lepore and H, and (ii) the detection of carriers of α° and β thalassaemia. It is recommended that subjects of all ethnic groups be screened for β‐thalassaemia trait, all except Northern European Caucasians for variant haemoglobins, and selected ethnic groups for α°‐thalassaemia trait. Testing for β‐thalassaemia trait should be carried out when the mean cellular haemoglobin (MCH) is < 27 pg and testing for α°‐thalassaemia trait should be considered when the MCH is < 25 pg. Appropriate methods include HPLC or haemoglobin electrophoresis for identification of variant haemoglobins and HPLC or microcolumn chromatography for quantification of haemoglobin A2.

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Screening criteria for beta thalassaemia trait in pregnant women.

Cited by 20 publications

References 2 publications

Risk of neural tube defects in the offspring of thalassaemia carriers in Hong Kong Chinese

Risk of neural tube defects in the offspring of thalassaemia carriers in Hong Kong Chinese

Screening for β-Thalassaemia Trait in Anaemic Pregnant Women

The Laboratory Diagnosis of Haemoglobinopathies

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