AB109. Noninvasive prenatal testing (NIPT): differences in testing indications between the US and Southeast Asia

Background and objective: Cell-free DNA-based noninvasive prenatal testing (NIPT) has been validated as a screening test for certain fetal aneuploidy in high-risk women. High-risk indications include advanced maternal age (AMA), positive serum screen result, abnormal fetal ultrasound findings, and a previous affected pregnancy. However, recent studies show the effectiveness of NIPT in all pregnant women, regardless of risk. Determine if there are global differences in NIPT implementation between centers in Southeast Asia and the United States (US).

Methods: We queried the Illumina laboratory database for NIPT samples originating from Southeast Asian countries and the United States. The ordering providers had the option of specifying clinical indications for testing on the test requisition form (TRF). Indications included: AMA, abnormal ultrasound, positive serum screen, history of increased risk, or other. Samples were reviewed and classified into one of the five indications listed above or classified as “multiple indications” if more than one indication was selected; samples without an indication selected were excluded. Test indications were compared between the Southeast Asian and US cohorts.

Results: There was a significant difference in the test indications of the two cohorts (P<0.001). The majority of samples from the US had AMA as the indication (70.1%) vs. 47.0% in Southeast Asia samples. A positive serum screen was a more common indication in Southeast Asia (31.5%) than in the US (8.4%). More US (11.6%) than Southeast Asian (3.7%) samples specified an abnormal ultrasound as a test indication. “Other”, indicated in 7.4% of Southeast Asian samples and 0.6% of US samples, covered a range of indications detailed by providers, including maternal anxiety, borderline risk on serum screening, and late entry to prenatal care. Interestingly, maternal anxiety was more commonly listed for Southeast Asia (4.6%) than US (0.1%) samples.

Conclusions: This study suggests differences in testing indications between the US and Southeast Asia. Centers in Southeast Asia appear to be using NIPT more often as a secondary screen, following a positive screen, whereas US centers appear to be using NIPT as a primary screen, particularly in AMA women. A potential explanation for differences in test indications could be access to care and reimbursement for testing. Further studies are needed to better understand the global differences in NIPT implementation.

Keywords: Noninvasive prenatal testing (NIPT); indications; Southeast Asia; United States