Current Down syndrome tests are only screening tests that do not diagnose Down syndrome, but rather estimate the risk that the fetus may be affected. Although these screening tests have had a fairly significant false positive rate, pregnant women and their doctors have relied on them for years because they were all that was available. However, a new DNA-based screening test has recently been developed.
High-risk women now have the option of undergoing a screening test that has a detection rate of greater than 99% for Down syndrome with a very low false positive rate. The MaterniT21 Plus test is a simple blood test that examines fetal DNA in maternal blood and can give accurate information to pregnant women about Down syndrome as well as two other common chromosomal abnormalities, trisomy 18 and trisomy 13. This test is currently only available to high-risk women.