UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Antenatal screening for Down’s syndrome: Revised nuchal translucency upper truncation limit due to improved precision of measurement

Vale, SH; Huttly, WJ; Wald, NJ; (2020) Antenatal screening for Down’s syndrome: Revised nuchal translucency upper truncation limit due to improved precision of measurement. Journal of Medical Screening 10.1177/0969141320937321. (In press). Green open access

[thumbnail of 0969141320937321.pdf]
Preview
Text
0969141320937321.pdf - Published Version

Download (309kB) | Preview

Abstract

Objective: To determine whether the improved precision of nuchal translucency (NT) measurement used in antenatal screening for Down’s syndrome observed over time as evidenced by a decrease in the multiple of the median (MoM) standard deviation requires a modification to the NT MoM truncation limits to maintain accurate risk estimation. Methods: Probability plots were derived from the measurements of NT MoM values used in a 2018 audit of 22,362 unaffected pregnancies. The plots were used to determine whether the NT MoM upper truncation limit should be lowered. Validation plots were used to assess the screening accuracy of Down’s syndrome risk estimates calculated from observed NT MoM values in the 22,362 unaffected pregnancies and 69 Down’s syndrome pregnancies for original and revised NT MoM truncation limits. Results: Probability plots indicated that with improved precision of NT measurements, there was deviation from a Gaussian distribution at less high MoM values than with less precise measurements. Validation plots showed that using the current NT MoM upper truncation limit of 2.5 MoM with improved precision NT measurements overestimates the Down’s syndrome risk (median risk in highest risk category expressed as an odds was 53.3:1 and observed prevalence was 1:1.1). The large discrepancy was corrected by changing the NT upper truncation limit to 2.0 MoM (median risk in highest risk category expressed as an odds was 1:1.78 and observed prevalence 1:2.7). Conclusion: The NT MoM upper truncation limit should be reduced from 2.5 to 2.0 MoM.

Type: Article
Title: Antenatal screening for Down’s syndrome: Revised nuchal translucency upper truncation limit due to improved precision of measurement
Open access status: An open access version is available from UCL Discovery
DOI: 10.1177/0969141320937321
Publisher version: https://doi.org/10.1177/0969141320937321
Language: English
Additional information: This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Health Informatics
URI: https://discovery.ucl.ac.uk/id/eprint/10127016
Downloads since deposit
105Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item