(256) Uptake of prenatal diagnostic testing before and after implementation of non-invasive prenatal screening

Thursday, January 30, 2025

10:30 AM – 12:30 PM

Submitting Author and Presenting Author(s)

Kristen Warncke, MD

Resident Physician
University of Texas Southwestern Medical Center
Dallas, Texas, United States

Coauthor(s)

Gayathri D. Vadlamudi, MD (she/her/hers)

Fellow
UT Southwestern Medical Center
Ypsilanti, MI, United States
JP

Jessica E. Pruszynski, PhD

University of Texas Southwestern
Dallas, Texas, United States
PS

Patricia Santiago-Munoz, MD

UT Southwestern Medical Center
Dallas, Texas, United States
Elaine L. Duryea, MD

Associate Professor
University of Texas Southwestern Medical Center
Dallas, Texas, United States

Objective: To compare the rate of invasive diagnostic testing before and after implementation of non-invasive prenatal screening (NIPS).

Study Design: We conducted a retrospective observational study 12 months before and after implementation of NIPS at a large county hospital. Prior to the availability of NIPS, all patients between 15-22 weeks were offered serum screening through the quadruple screen. Starting August 2023, this was replaced by universal implementation of NIPS for patients ≥ 10 weeks gestation using a non-sequencing based rolling circle replication on-site assay (Vanadis system, PerkinElmer, Waltham, MA, USA). In both groups, individuals with abnormal screening results were offered invasive diagnostic testing. Diagnostic testing rates following abnormal screening and other indications including fetal anomalies or targeted gene analysis were compared using Chi-square.

Results:

From August 2022 to August 2023, of 13,533 patients receiving prenatal care, 7,149 patients underwent quadruple screening. In this group, 466 screened positive for trisomy 18 or trisomy 21, and 26 (5.6%) of these patients elected invasive diagnostic testing. Of the patients who elected diagnostic testing following an abnormal quad screen, aneuploidy was confirmed in 6 (23.1%). From August 2023 through July 2024, 11,631 (82.3%) of 14,127 patients receiving prenatal care underwent NIPS. In this group, 106 screened positive for either trisomy 13, 18, or 21. Diagnostic testing was elected by 22 (20.8%) of these patients, and aneuploidy confirmed in 10 (45.5%). The rate of invasive diagnostic procedures performed for any indication in the overall population did not change between the time epochs (116/13,533 vs 100/14,127, p=0.16).

Conclusion: The rate of invasive diagnostic testing remained unchanged following the implementation of NIPS. However, following an abnormal screening result, the rate at which patients opted for invasive diagnostic testing increased fourfold, while the rate of diagnostic confirmation of aneuploidy through invasive testing rose twofold compared to the use of the serum screen.