NIPT is a blood test done on the mother (usually after 10 weeks of gestation) that analyzes cell-free fetal DNA (cffDNA) circulating in maternal blood. It screens for common chromosomal conditions — primarily Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome), and Trisomy 13 (Patau syndrome) and can also screen for sex chromosome variations.

NIPT has a much higher sensitivity and specificity than traditional biochemical screening (double/quad marker tests) for the common trisomies, with detection rates typically above 99% for Trisomy 21.

Who should care:

*Patients with an abnormal double marker, triple marker, or quad screen
*Patients with soft markers on ultrasound
*Advanced maternal age (35+)
*Anyone wanting a highly sensitive screening option, regardless of background risk

NIPT is typically offered from 10 weeks gestation onward. It’s a screening test, not a replacement for diagnostic testing when a definitive answer is required (e.g., before major medical decisions).

A low-risk NIPT result significantly reduces anxiety and often avoids the need for invasive testing. A high-risk NIPT result prompts a diagnostic test (amniocentesis or CVS) for confirmation before any clinical decision is made.

Limitations:

NIPT is a screening test, not diagnostic — a “high risk” result must be confirmed with amniocentesis or CVS.
False positives and false negatives, while rare, do occur.
It does not screen for all genetic or structural conditions — a normal NIPT does not rule out other issues (e.g., structural anomalies still require ultrasound follow-up).
Placental mosaicism or vanishing twin can occasionally cause discordant results.