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Should cell‐free fetal DNA be included in first trimester screening (FTS) for common trisomy? A possible scenario on 6697 women screened over 10 years
Author(s) -
Rosignoli Lucia,
Tonni Gabriele
Publication year - 2016
Publication title -
journal of evaluation in clinical practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.737
H-Index - 73
eISSN - 1365-2753
pISSN - 1356-1294
DOI - 10.1111/jep.12557
Subject(s) - medicine , trisomy , cell free fetal dna , obstetrics , gynecology , population , fetus , audit , first trimester , pregnancy , risk assessment , prenatal diagnosis , biology , genetics , environmental health , computer security , management , computer science , economics
Objective The primary aim was to determine the performance of the first trimester screening (FTS) test in a general obstetrics population. Cost‐benefit analysis of a hypothetic model based on implementation of the FTS test by cell‐free fetal (cff) DNA was calculated. Methods A total of 6697 women were screened using FTS test. A two‐step strategy based upon nuchal translucency, serum screening and ultrasound assessment of nasal bone (NB) was applied. Three groups were identified (high‐risk: >1:250; intermediate‐risk: 1:251–1:999 and low‐risk group: <1:1000). Women at intermediate‐risk (1:251–1:999) underwent NB assessment and recalculation of individual risk. All women at high‐risk were offered fetal karyotyping. Results A total of 321 women (4.8%) resulted at high‐risk while 480 women (7.1%) with intermediate‐risk underwent assessment of the NB, which was absent in 15 fetuses. Overall, 54 aneuploidies were detected for a 96.4% sensitivity, a 96.1% specificity, a 99.9% negative predictive value and a false positive rate of 4.8%. Audit was conducted on a yearly basis and lost to follow up was 0.47% (32 cases). Conclusions Public health system would not be able to cover the cost of including cff DNA in women undergoing first trimester screening on universal basis. However, assuming a possible scenario based on implementation of FTS by cff DNA in women at high‐risk would result in a 6‐fold reduction in the number of invasive procedures while avoiding two false negative results (trisomy 21) that were diagnosed in women with intermediate‐risk using current screening strategy by combined test.