Population-based prenatal screening for open neural tube defects and Down syndrome
presents special challenges to the laboratory. Screening for these serious disorders
is offered to low-risk, apparently healthy women with no prior indication of problems
with their developing baby. After agreeing to be tested, the first indication of a
potential problem occurs when the health care provider informs the woman that the
results of her screening test are “positive.” These women then are offered genetic
counseling and follow-up testing (eg, ultrasound examination or diagnostic amniocentesis);
however, the majority of positive test results are false positives. Depending on the
combination of markers and the trimester in which screening is offered, only 1% to
3% of these screen-positive women have true positive results (ie, associated with
an open fetal defect or chromosomal abnormality) [
1
,
2
,
3
]. Thus, a large burden of the screening process falls on those women with false-positive
results with consequences that include increased anxiety, labeling, increased costs
associated with follow-up testing, and procedure-related losses of healthy fetuses.
Achieving and maintaining the proper balance between detecting the target disorder
while maintaining an acceptably low false-positive rate (FPR) requires careful and
ongoing monitoring of screening performance along with specific procedures aimed at
taking rapid and effective corrective actions when warranted.To read this article in full you will need to make a payment
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References
- Prenatal screening for Down's syndrome with use of maternal serum markers.N Engl J Med. 1992; 327: 588-593
- Reducing the need for amniocentesis in women age 35 years of age and older with serum markers for screening.N Engl J Med. 1994; 330: 1114-1118
- Screening of maternal serum for fetal Down's syndrome in the first trimester.N Engl J Med. 1998; 338: 955-961
- Quality management.in: Burtis C.A Ashwood E.R Tietz textbook of clinical chemistry. 2nd edition. W.B. Saunders Co, Philadelphia1993: 548-592
- Wald N Leck I Antenatal and neonatal screening. 2nd edition. Oxford University Press, Oxford (UK)2000: xii
- Maternal serum-alpha-fetoprotein measurement in antenatal screening for anencephaly and spina bifida in early pregnancy. Report of the UK collaborative study on alpha-fetoprotein in relation to neural-tube defects.Lancet. 1977; 1: 1323-1332
- Variables which influence the levels of AFP, uE3, and hCG and/or risk for down syndrome.in: Haddow J.E Palomaki G.E Knight G.J Canick J.A Prenatal screening for major fetal disorders. Down syndrome. Vol. II. Foundation for Blood Research, Scarborough, ME1998
- Maternal serum screening for Down's syndrome in early pregnancy.BMJ. 1988; 297: 883-887
- National Institute of Child Health and Human Development. The quality control of alpha-fetoprotein reagents and assay for the antenatal screening and diagnosis of open neural tube defects.Clin Chem Acta. 1980; 105: 9-24
- FBR/CAP Maternal Screening Survey: Participant Summary Report. FP-A 2000.College of American Pathologists, Northfield (IL)2002
- Maternal serum alpha-fetoprotein: a problem with a test kit.N Engl J Med. 1986; 314: 516
- Assessing reliability of AFP test kits.Contemp Ob Gyn. 1987; 30: 37-52
- Selection and validation of alpha-fetoprotein assay kits for Down syndrome.Am J Obstet Gynecol. 1987; 156: 1557-1559
- Epidemiologic monitoring and quality control of prenatal screening.in: Sturgeon C.M Seth J Middle J.G Halloran S.P Proceedings of the UK NEQAS meeting. 1. Association of Clinical Biochemists Ltd, London1995: 120-126
- Quality assessment of a prenatal screening program.Early Hum Dev. 1996; 47: S49-S53
- Racial difference and biological significance of maternal serum alpha fetoprotein.Lancet. 1986; 2: 573
- Vital Health Statistics 2000 Natality Data Set [database on CD-ROM]. Series 21, Number 14.Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, Hyattvill (MD)April 2002
- Refinements in managing maternal weight adjustment for interpreting prenatal screening results.Prenat Diagn. 1996; 16: 1115-1119
- Use of maternal serum alpha-fetoprotein measurements to screen for Down's syndrome.Clin Obstet Gynecol. 1988; 31: 306-327
- UK multicentre project on assessment of risk of trisomy 21 by maternal age and fetal nuchal-translucency thickness at 10–14 weeks of gestation. Fetal Medicine Foundation First Trimester Screening Group.Lancet. 1998; 352: 343-346
- One stop clinic for assessment of risk for fetal anomalies: report of the first year of prospective screening for chromosomal anomalies in the first trimester.Br J Obstet Gynaecol. 2000; 107: 1271-1275
- Combining ultrasound and biochemistry in first-trimester screening for Down's syndrome.Prenat Diagn. 1997; 17: 821-829
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