Getting a False Positive on a Screening Test

A New Screening Test

Another test gaining popularity is the first-trimester screening, which combines an ultrasound that measures the amount of thickening at the back of the neck (a sign of Down syndrome) with a blood test. The test is also known as the Nuchal Fold test. Since this test is relatively new in the United States, it may not be available in all areas, and those administering the test must be highly trained to provide the most accurate results. Yet, as a screening test you can still anticipate false positives.

Diagnostic Tests: Amniocentesis and Chorionic Villus Sampling (CVS)

A positive screening test result may indicate that you should consider additional testing to determine your baby's health. A "diagnostic" test can make the actual diagnosis.

The amniocentesis and CVS tests involve more invasive procedures. For an amniocentesis, doctors insert a needle into the abdomen and uterus to extract amniotic fluid. A CVS involves placing a thin tube into the uterus through the cervix or through inserting a needle into abdominal wall. Then, a doctor suctions out a tiny piece of the placenta.