Lab Med Online.  2011 Jan;1(1):10-18.

The Evaluation of Integrated Test as an Antenatal Screening Test for Down's Syndrome in Korea

• Yi DY
• Jung B
• Kang MS
• Huh JY
• Paek JY
• Cha DH
• Kang SH

Abstract

BACKGROUND
Antenatal screening for Down's syndrome has been developed and improved over the past 20 yr. Recently, integrated test, which combines the first and second trimester markers has shown the highest detection rate (DR) and lowest false positive rate (FPR) among Down's syndrome screening tests currently in use. The purposes of this study were to evaluate the screening performance of integrated test and to compare the results with triple test studies in Korea.
METHODS
The study population consisted of Korean pregnant women who underwent triple or integrated test between April 2005 and December 2008. Triple test was performed using measurements of alpha-fetoprotein (AFP), unconjugated estriol (uE3), and human chorionic gonadotropin (hCG) in the second trimester. Integrated test was performed using nuchal translucency (NT) by ultrasonography and pregnancy-associated plasma protein A (PAPP-A) from maternal serum in the first trimester, and AFP, uE3, hCG, and inhibin-A in the second trimester. The screening performance of each test was evaluated by DR and FPR.
RESULTS
Twenty-seven Down's syndrome pregnancies were confirmed in women screened by triple (N=6,736) or integrated test (N=7,688). At 1:100, 1:270, and 1:300 of risk cutoff, triple test showed 45%, 73%, and 73% of DR and 4.7%, 11.2%, and 12.4% of FPR, respectively. At 1:100, 1:150, and 1:300 of risk cutoff, integrated test showed 63%, 69%, and 75% of DR and 1.5%, 1.9%, and 3.0% of FPR, respectively.
CONCLUSIONS
Integrated test showed higher DR and lower FPR, demonstrating better screening performance than triple test.

Keyword

Down's syndrome; Integrated test; Triple test; Detection rate; False positive rate

MeSH Terms

alpha-Fetoproteins
Chorionic Gonadotropin
Down Syndrome
Estriol
Female
Humans
Korea
Mass Screening
Nuchal Translucency Measurement
Plasma
Pregnancy
Pregnancy Trimester, First
Pregnancy Trimester, Second
Pregnant Women
Prenatal Diagnosis
Staphylococcal Protein A
Chorionic Gonadotropin
Estriol
Staphylococcal Protein A
alpha-Fetoproteins

Figure

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  Fig. 1 Flow chart of screening for Down's syndrome pregnancy by triple test.

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  Fig. 2 Estimated risk for Down's syndrome pregnancies and selected centiles of unaffected pregnancies in triple test.

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  Fig. 3 Flow chart of screening for Down's syndrome pregnancy by integrated test.

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  Fig. 4 Estimated risk for Down's syndrome pregnancies and selected centiles of unaffected pregnancies in integrated test.

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