NT is a screening test that helps estimate the risk of Down syndrome and a few other chromosomal conditions. The test measures the amount of fluid in the tissue at the back of your baby’s neck (nuchal translucency). Babies with an increased amount of fluid have an increased chance of having Down syndrome or another chromosomal condition. It is important to note that the test does not detect all cases of Down syndrome or other chromosomal conditions. NT is a prenatal ultrasound measurement of the baby’s translucent area at the back of the neck. The measurement can assist in screening for chromosomal abnormalities including Down syndrome.