Cost-effectiveness analysis for triple markers serum screening for Down's syndrome in Thai setting

Clinical experience from Thailand: noninvasive prenatal testing as screening tests for trisomies 21, 18 and 13 in 4736 pregnancies

PURPOSE

The purpose of this article is to report the clinical experience and performance of massively parallel sequencing-based noninvasive prenatal testing (NIPT) as a screening method in detecting trisomy 21, 18, and 13 (T21/T18/T13) in a mixed-risk population in Thailand.

METHODS

In a 30-month period, 121 medical centers in Thailand offered NIPT as clinical screening tests for fetal T21, T18, and T13 in the mixed-risk population. All NIPT-positive cases were recommended to undergo invasive prenatal diagnosis.

RESULTS

A total of 4736 participants received the NIPT test, including 2840 high-risk pregnancies, either with advanced maternal age or positive serum biochemical tests, and 1889 low-risk pregnancies without conventional indications; 99.9% (4732/4736) of the participants with a median maternal age of 35 years old received reports, and 1.3% (63/4732) were classified as test positive, including 36 T21, 19 T18, and 8 T13; 82.5% (52/63) took prenatal diagnosis, and 11.5% (6/52) false-positive cases were observed. The positive predictive values for the detection of T21, T18, and T13 were 94.4%, 79.0%, and 87.5%, respectively.

CONCLUSION

With stringent protocol, our prospective large-scale multicenter nationwide study demonstrated that NIPT showed excellent performance as screening tests for the detection of fetal T21, T18, and T13 in mixed-risk pregnancies in Thailand.