Document Detail

Integrated screening for Down's syndrome on the basis of tests performed during the first and second trimesters.
MedLine Citation:
PMID:  10441601     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Both first-trimester screening and second-trimester screening for Down's syndrome are effective means of selecting women for chorionic-villus sampling or amniocentesis, but there is uncertainty about which screening method should be used in practice. We propose a new screening method in which measurements obtained during both trimesters are integrated to provide a single estimate of a woman's risk of having a pregnancy affected by Down's syndrome. METHODS: We used data from published studies of various screening methods employed during the first and second trimesters. The first-trimester screening consisted of measurement of serum pregnancy-associated plasma protein A in 77 pregnancies affected by Down's syndrome and 383 unaffected pregnancies and measurements of nuchal translucency obtained by ultrasonography in 326 affected and 95,476 unaffected pregnancies. The second-trimester tests were various combinations of measurements of serum alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin, and inhibin A in 77 affected and 385 unaffected pregnancies. RESULTS: When we used a risk of 1 in 120 or greater as the cutoff to define a positive result on the integrated screening test, the rate of detection of Down's syndrome was 85 percent, with a false positive rate of 0.9 percent. To achieve the same rate of detection, current screening tests would have higher false positive rates (5 to 22 percent). If the integrated test were to replace the triple test (measurements of serum alpha-fetoprotein, unconjugated estriol, and human chorionic gonadotropin), currently used with a 5 percent false positive rate, for screening during the second trimester, the detection rate would be higher 85 percent vs. 69 percent), with a reduction of four fifths in the number of invasive diagnostic procedures and consequent losses of normal fetuses. CONCLUSIONS: The integrated test detects more cases of Down's syndrome with a much lower false positive rate than the best currently available test.
N J Wald; H C Watt; A K Hackshaw
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The New England journal of medicine     Volume:  341     ISSN:  0028-4793     ISO Abbreviation:  N. Engl. J. Med.     Publication Date:  1999 Aug 
Date Detail:
Created Date:  1999-08-12     Completed Date:  1999-08-12     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0255562     Medline TA:  N Engl J Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  461-7     Citation Subset:  AIM; IM    
Department of Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, St. Bartholomew's and the Royal London School of Medicine and Dentistry, United Kingdom.
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MeSH Terms
Chorionic Gonadotropin / blood
Down Syndrome / diagnosis*
Estriol / blood
False Positive Reactions
Genetic Testing
Inhibins / blood
Likelihood Functions
Maternal Age
Neck / ultrasonography
Normal Distribution
Pregnancy Trimester, First
Pregnancy Trimester, Second
Pregnancy-Associated Plasma Protein-A / analysis
Prenatal Diagnosis / methods*
Sensitivity and Specificity
alpha-Fetoproteins / analysis
Reg. No./Substance:
0/Chorionic Gonadotropin; 0/alpha-Fetoproteins; 50-27-1/Estriol; 57285-09-3/Inhibins; EC 3.4.24.-/Pregnancy-Associated Plasma Protein-A
Comment In:
N Engl J Med. 1999 Aug 12;341(7):521-2   [PMID:  10441609 ]
N Engl J Med. 1999 Dec 16;341(25):1935; author reply 1936   [PMID:  10610478 ]
N Engl J Med. 1999 Dec 16;341(25):1935; author reply 1936   [PMID:  10610477 ]
N Engl J Med. 1999 Dec 16;341(25):1935-6; author reply 1937   [PMID:  10610479 ]

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