Maternal blood test for Downs imminent

A DNA test to detect trisomy 21 from fetal DNA circulating in maternal blood has been hailed “the beginning of a revolution” by an Australian obstetrician.

In a study of 480 women at risk for fetal trisomy 21, plasma DNA sequencing correctly identified 39 cases and one false positive, giving a sensitivity of 100% and a specificity of 99.7%, US researchers said. 

Adelaide obstetrician Professor Jeffrey Robinson, from the Robinson Institute, said the study, the third in a series, was approaching the size needed to validate the non-invasive test in a clinical setting.

“It’s quite an important change that we will have to think about if you can offer people definitive testing from a blood test,” he said.

“You have to counsel such people about what are the benefits and risks and what they’ll have to consider next.”

The researchers indicated that additional improvements will be