Blood Test Detects Down Syndrome (and More) with No Risk to Fetus (Part 2)

According to the researchers, the accuracy of the new test was demonstrated in a small study of 18 women and a single male donor where the nine women having a Down syndrome pregnancy were correctly identified. In addition, the test identified two of the women as carrying fetuses with Edward syndrome and one carrying a fetus with Patau syndrome. The test detected every genetic defect and was able to identify every normal pregnancy as well as the male donor.

According to Quake in a telephone interview, “It's the first universal, noninvasive test for Down syndrome. So this should be the first step in putting an end to invasive testing procedures like amniocentesis and chorionic villus sampling.”

Although there are some other noninvasive prenatal tests available, such as the ultrasound, and blood tests like the alpha-fetoprotein test that can find potential signs of a chromosomal disorder such as Down syndrome, they cannot diagnose with certainty. Quake said that these tests are “indirect and weak predictors of what's going on.”

Quake said the next step is to perform a much larger study and that the new test could be widely available in two or three years, possibly becoming a routine prenatal test of a baby's health. Currently, the test would cost about $700. But that cost would drop considerably if it were widely used. The study can be found in the journal Proceedings of the National Academy of Sciences.