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Clinical experience and follow-up with l... [Am J Obstet Gynecol. 2014] - PubMed - NCBI

Reproductive Health

Clinical experience and follow-up with large scale single-nucleotide polymorphism-based non-invasive prenatal aneuploidy testing

Dar P, et al. Am J Obstet Gynecol 2014 Aug

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Judith M. Orvos, Contemporary ObGyn, August 5, 2014

2014 Aug 8. pii: S0002-9378(14)00818-7. doi: 10.1016/j.ajog.2014.08.006. [Epub ahead of print]

Clinical experience and follow-up with large scale single-nucleotide polymorphism-based non-invasive prenatal aneuploidy testing.

Dar P1, Curnow KJ2, Gross SJ2, Hall MP2, Stosic M2, Demko Z2, Zimmermann B2, Hill M2, Sigurjonsson S2, Ryan A2, Banjevic M2, Kolacki PL3, Koch SW3,Strom CM3, Rabinowitz M4, Benn P5.

Author information

Abstract

OBJECTIVE:

To report on laboratory and clinical experience following six months of clinical implementation of a single-nucleotide polymorphism (SNP)-based non-invasive prenatal aneuploidy test in high- and low-risk women.

STUDY DESIGN:

All samples received between March and September 2013 and drawn after 9 weeks' gestation were included. Samples that passed quality control were analyzed for trisomy 21, trisomy 18, trisomy 13, and monosomy X. Results were reported as high or low risk for fetal aneuploidy for each interrogated chromosome. Relationships between fetal fraction and gestational age and maternal weight were analyzed. Follow-up on outcome was sought for a sub-set of high-risk cases. False negative results were reported voluntarily by providers. Positive predictive value (PPV) was calculated from cases with an available pre- or postnatal karyotype or clinical evaluation at birth.

RESULTS:

Samples were received from 31,030 patients, 30,705 met study criteria, and 28,739 passed quality control metrics and received a report detailing aneuploidy risk. Fetal fraction correlated positively with gestational age, and negatively with maternal weight. Five-hundred and seven patients received a high-risk result for any of the four tested conditions (324 trisomy 21, 82 trisomy 18, 41 trisomy 13, 61 monosomy X; including one double aneuploidy case). Within the 17,885 cases included in follow up analysis, 356 were high-risk, and outcome information revealed 184 (51.7%) true positives, 38 (10.7%) false positives, 19 (5.3%) with ultrasound findings suggestive of aneuploidy, 36 (10.1%) spontaneous abortions without karyotype confirmation, 22 (6.2%) terminations without karyotype confirmation, and 57 (16.0%) were lost to follow-up. This yielded an 82.9% PPV for all aneuploidies, and a 90.9% PPV for trisomy 21. The overall PPV for women over 35 was similar to the PPV for women under 35 years. Two patients were reported as false negatives.

CONCLUSIONS:

The data from this large-scale report on clinical application of a commercially available NIPT suggests that the clinical performance of this SNP-based NIPT in a mixed high and low risk population is consistent with performance in validation studies.