J Korean Med Sci.  2006 Feb;21(1):11-14. 10.3346/jkms.2006.21.1.11.

Threshold of Nuchal Translucency for the Detection of Chromosomal Aberration: Comparison of Different Cut-offs

• Kim MH
• Park SH
• Cho HJ
• Choi JS
• Kim JO
• Ahn HK
• Shin JS
• Han JY
• Kim MY
• Yang JH

• KMID: 2157774
• DOI: http://doi.org/10.3346/jkms.2006.21.1.11

Abstract

This study evaluated the sensitivities and false positive rates of the screening test using ultrasonographic measurement of thickness of nuchal translucency (NT) with different cut-offs for chromosomal aberration in a Korean population. We included 2,570 singleton pregnancies undergoing ultrasound between 11 weeks and 14 weeks of gestation in this study. We analyzed the sensitivities of NT alone for screening chromosomal aberration using three cut-offs -2.5 mm, 3.0 mm, and 95th percentile for each crown rump length (CRL). There were 31 chromosomal aberrations (1.2%) including 12 cases of trisomy 21. The numbers of chromosomal aberrations that were detected by NT with different cut-offs of 2.5 mm, 3.0 mm and the 95th percentile CRL were 22, 18 and 23, respectively. At a threshold of 2.5 mm, the sensitivity and the false positive rate for total chromosomal aberrations were 67.7% and 6.3%, respectively. At 3.0 mm, those were 54.8% and 3.5%, respectively. At the 95th percentile CRL, those were 70.9% and 5.8%, respectively. The use of CRL-dependent cut-offs for nuchal translucency improves the detection of chromosomal aberrations when compared to fixed cut-offs in a Korean population.

Keyword

Nuchal Translucency Measurement; Sensitivity & Specificity; Chromosome Aberrations

MeSH Terms

Adult
*Chromosome Aberrations
Chromosome Disorders/diagnosis
Comparative Study
Female
Fetal Diseases/*diagnosis/genetics
Humans
Mass Screening/methods
Nuchal Translucency Measurement/*methods
Pregnancy
Sensitivity & Specificity

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