New blood test for Down syndrome offered in Boston area
Pregnant women over age 35 in the Boston area can now get a blood test from their doctor to screen their fetus for Down syndrome. The new test, made by Sequenom, was rolled out in Boston and 19 other metropolitan areas across the country on Monday.
The test, which looks for fetal markers present in the mother’s blood, can be given as early as 10 weeks of pregnancy and is less invasive than chorionic villus sampling and amniocentesis -- both of which involve drawing a small sample of amniotic fluid and carry a small risk of miscarriage.
At the moment, the company says the test -- called MaterniT21 -- is appropriate only for use in high-risk women including anyone age 35 or older; younger women who have Down in their family or who have had a suspicious finding on an ultrasound may also be offered the test.
In a study published this week in the journal Genetics in Medicine, the blood test was able to detect 98.6 percent of the fetuses with Down syndrome -- or 209 cases -- in 4,664 high-risk pregnancies; the test falsely detected Down in 0.2 percent of pregnancies. Women who had a negative result could be 99 percent certain that they didn’t have a fetus with Down.
Further research would need to examine the test’s reliability in low-risk women before it could be offered to them. Medical tests generally prove to be less accurate in those who are less likely to have the condition being screened.
While the blood test may not completely eliminate CVS or amniocentesis, it and others about to hit doctors’ offices may dramatically cut down on the number of these procedures performed, largely limiting them to women with positive blood test results.
But that could take some time since doctors may be slow to offer the new test. Part of the problem is its cost, which isn’t now covered by managed care networks. Women will typically have to pay a considerable amount out of pocket beyond what their insurance will cover for the $1,900 test. “At this point Sequenom expects the cost to insured patients to be no more than $235 out of pocket, as we engage payers (including Mass. health plans) in contract negotiations,” spokesperson Jakob Jakobsensaid in an e-mail.
That expense might make women more likely to opt for a standard noninvasive screening currently used -- a combination blood test and ultrasound technique that’s 95 percent accurate at predicting Down.
Advocates of those with Down Syndrome have expressed concern over technology making it easier to detect Down early in pregnancy -- and easier to terminate pregnancies as a result. And this new test is one more advance sounding alarm bells.
A smaller number of people with Down means less financial and social support, said Maureen Gallagher, executive director of the Massachusetts Down Syndrome Congress. “We see this as a new sense of urgency to educate the public that people with Down syndrome can lead meaningful lives, with many living into their 60s and 70s.”
Gallagher and her colleagues have been working with local maternity hospitals and obstetrician practices in an effort to get them to provide educational resources to any couple who find out they’re having a baby with Down. (Couples can get them on their own by e-mailing email@example.com or calling 800-664-MDSC.)
“We’re heard of cases where doctors have been too quick to push for termination,” she said, “and have found a significant number of families who felt they didn’t have the full story about Down.”
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