Evolution in screening of down syndrome

M R C O G PA R T 2 · S O S P O C K E T C A R D · K N O W L E D G E A R E A 5 – A N T E N ATA L C A R E

Evolution in Screening of Down Syndrome Ashoor Al Mahri G, Nicolaides KH. Evolution in screening of Down syndrome. TOG 2019;21:51–57. doi:10.1111/tog.12534

30% 60–75% 90% DR, MATERNAL AGE ALONE (5% FPR) DR, 2ND-TRIMESTER BIOCHEMISTRY (5% FPR) DR, COMBINED 1ST-TRIMESTER TEST (5% FPR)

DO N' T-M IS S FA C TS

1. Maternal age alone: 30% DR at 5% FPR

2. Second-trimester serum biochemistry: 60–75% DR at 5% FPR

3. First-trimester combined test (NT + biochemistry): 90% DR at 5% FPR

4. Cell-free DNA: 99% DR at 0.1% FPR — best performing, but currently expensive

5. Proposed feasible model: offer cfDNA contingent on first-line combined-test result, not as universal first-line test

6. Source is abstract-level only — verify details against full TOG article before relying on this for exam depth

SCREENING GENERATIONS AT A GLANCE

Maternal age: 30% DR / 5% FPR 2nd-tri biochemistry: 60–75% DR / 5% FPR Combined test: 90% DR / 5% FPR

cfDNA: 99% DR / 0.1% FPR

ABBREVIATION KEY

DR — detection rate cfDNA — cell-free DNA

FPR — false positive rate TOG — The Obstetrician & Gynaecologist

NT — nuchal translucency

Notes prepared from Ashoor Al Mahri G, Nicolaides KH. The Obstetrician & Gynaecologist 2019;21:51–57 · doi:10.1111/tog.12534 · Based on abstract-level source content only — full text could not be retrieved; verify against the original TOG article for additional detail.

Source: The Obstetrician & Gynaecologist (TOG), RCOG journal — Ashoor Al Mahri G, Nicolaides KH. Evolution in screening of Down syndrome. TOG 2019;21:51–57. doi:10.1111/tog.12534

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