Most current prenatal testing approaches like amniocentesis or chorionic villus sample include a certain degree of risk of miscarriage, but cell-free DNA testing relies on a blood sample, potentially changing what disorders can be looked for, Erin Biba at Wired writes. "Based on a small sample of a woman's blood, the cell-free fetal DNA test gives expectant mothers an earlier (and safer) look than ever at just who it is that's growing inside them," she adds. Tests from Sequenom, Verinata, and Ariosa Diagnostics are entering the marketplace to do just that.
Currently, Biba writes, most tests are for trisomies or other chromosomal disorders, but that could change. John Stuelpnagel from Ariosa tells her that future tests should focus on clear diagnoses for severe diseases or diagnoses for mild diseases that can be treated easily. "The genetic disorder must be well understood," Stuelpnagel says. "It does not benefit anyone if there is ambiguity in diagnosis created by a test."