NIPT is used most widely to describe genetic tests that use cell-free DNA (cfDNA) circulating in maternal blood to detect fetal trisomy 21, 18, and 13, as well as other chromosomal disorders. This is in contrast to invasive tests that require samples obtained by amniocentesis or chorionic villus sampling, procedures that are associated with a low risk of miscarriage.
Importantly, cfDNA NIPTs are screening tests, whereas invasive te stsare diagnostic. Screening tests for fetal aneuploidies aren’t new.Biochemical tests for fetal aneuploidies, such as the quadruple screen,have been performed for nearly 30 years. A key distinction between biochemical and cfDNA screening tests is the greater accuracy of the latter.
Understanding Non-Invasive Prenatal Testing - AACC.org