Overview
What the Test Measures
Non invasive prenatal testing (NIPT) is a maternal blood test that analyses circulating cell free DNA fragments released mainly from placental trophoblast cells.
Non-invasive prenatal testing (NIPT) is a maternal blood test that analyses circulating cell-free DNA fragments released mainly from placental trophoblast cells. The sample is obtained from the pregnant patient’s blood; it does not directly sample fetal cells. The laboratory uses the placental DNA pattern to estimate the likelihood of the common fetal trisomies: - Trisomy 21 - Trisomy 18 - Trisomy 13 NIPT is therefore a screening test, not a diagnostic test. It produces a risk estimate. It does not prove that the fetus has, or does not have, a chromosomal condition. Placental DNA usually reflects the fetal chromosome pattern, but the placenta and fetus are not the same tissue. That distinction explains why a high-risk result can occasionally occur when the fetus is unaffected, or why a low-risk result cannot exclude every chromosomal condition. The test is a risk flag, not a final diagnosis.