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The “Consecutive Combined Test”—using Double test from week 8 + 0 and Nuchal Translucency Scan, for first trimester screening for Down Syndrome
Author(s) -
Schiøtt Kirsten Marie,
Christiansen Michael,
Petersen Olav Bjørn,
Sørensen Tina Lind,
Uldbjerg Niels
Publication year - 2006
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.1487
Subject(s) - medicine , nuchal translucency , trisomy , aneuploidy , down syndrome , population , test (biology) , triple test , nuchal translucency measurement , gestational age , obstetrics , gynecology , pregnancy , predictive value , first trimester , gestation , fetus , biology , paleontology , biochemistry , environmental health , psychiatry , gene , chromosome , genetics
Abstract Objective To test the performance of the “Consecutive Combined Test”, applied on a high‐risk population. The classic “Combined Test” (Double test (DT) and Nuchal Translucency (NT) measurement on the same day at app. week 12) gives detection rates (DR) for Down syndrome (DS) of 80–90% for false positive rates (FPR) of 5%. In affected pregnancies, however, the low PAPP‐A level is more pronounced, the earlier in pregnancy. Thus, we hypothesized that the Double Test could be taken as early as from week 8 + 0, without compromising the excellent performance of the Combined Test. This “Consecutive Combined Test” allows for a centralised laboratory function. Methods Inclusion criteria were maternal age > 35 years (80%) or a family history (20%). Double test was taken at a median gestational age (GA) = 10 weeks. NT was measured at GA = 11 + 0 − 13 + 6. A combined risk estimate of > 1:400 at birth was used as cut‐off. Results 881 had the full test. Screen positive = 34. CVS with aneuploidy = 11 (6 trisomy‐21, 5 others). FPR = 3.2%. Positive Predictive Value (PPV) = 17.6% for T‐21. Conclusion The “Consecutive Combined Test” applied on a high‐risk population seems to be highly efficient with a remarkably high PPV. Copyright © 2006 John Wiley & Sons, Ltd.