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Maternal serum–integrated screening for trisomy 18 using both first‐ and second‐trimester markers
Author(s) -
Palomaki Glenn E.,
Neveux Louis M.,
Knight George J.,
Haddow James E.
Publication year - 2003
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.572
Subject(s) - trisomy , down syndrome , obstetrics , aneuploidy , pregnancy , medicine , estriol , odds ratio , population , false positive rate , human chorionic gonadotropin , gynecology , pregnancy associated plasma protein a , first trimester , fetus , biology , genetics , chromosome , statistics , mathematics , environmental health , psychiatry , gene
Abstract Objectives To estimate the prenatal screening performance of an integrated serum test for detecting trisomy 18, which combines measurements of first‐ and second‐trimester markers with maternal age to assign patient‐specific risks. Methods Published and new observations of maternal serum marker levels in trisomy 18 and unaffected pregnancies are used to derive population parameters. These parameters are then combined in a multivariate Gaussian model to assign patient‐specific risks for trisomy 18. Results The best combination of serum markers includes pregnancy‐associated plasma protein‐A in the first trimester and alpha‐fetoprotein, unconjugated estriol and human chorionic gonadotropin in the second trimester. At a second‐trimester risk cutoff of 1 : 100, these 4 markers, in combination with maternal age, detect 90% of trisomy 18 pregnancies at a false‐positive rate of 0.1%. The odds of a trisomy 18 pregnancy among screen‐positive women are 1 : 4. Without the first‐trimester marker, detection is reduced to 67% at about the same false‐positive rate. Conclusion The algorithm described here is highly efficient for detecting trisomy 18 and should be considered by programs that offer serum‐integrated screening for Down syndrome. Copyright © 2003 John Wiley & Sons, Ltd.