Prenatal Screenings for Disorders Often Wrong

(Decision Magazine) In a recently published investigative report by The New York Times, data revealed that blood tests meant to detect rare conditions and disorders in preborn babies produce false positives 81-93% of the time.

The months-long investigation included interviews with genetic counselors and experts on medical testing and prenatal care, as well as six peer-reviewed studies of screenings by U.S.-based labs that included follow-up diagnostic testing.

The noninvasive prenatal test technology, referred to as NIPT, takes blood drawn from the mother during the first trimester to screen the fetus’ DNA for any potential developmental issue. 

NIPTs have a very high success rate of detecting common disorders, such as Down syndrome. But as prenatal testing has grown in popularity over the last decade, manufacturers have tried to outsell each other, and have started offering additional screenings for increasingly rare conditions.

According to the Times’ report, “The grave predictions made by those newer tests are usually wrong.”

For example, studies suggest that there is an 81% chance that a positive test result for DiGeorge syndrome—a primary immunodeficiency that can cause heart defects and delayed language acquisition—is wrong.

For Prader-Willi and Angelman syndromes—two genetic disorders characterized by seizures and the inability to control food consumption—the percentage of false positives are even greater, at 93%. 

Sarah Kliff, co-author of the report alongside Aatish Bhatia, says that this type of information rarely makes its way into patient brochures or laboratory result sheets though. Why? 

“One reason is that the FDA does not regulate these tests or the marketing claims manufacturers make,” she says

Kliff and Bhatia’s report includes links to marketing materials from companies like Quest Diagnostics, Myriad Genetics and Roche claiming to offer patients “peace of mind,” “total confidence in every result” and “information [they] can trust.”

“Some of the companies offer tests without publishing any data on how well they perform,” the report explains, “or point to numbers for their best screenings while leaving out weaker ones. Others base their claims on studies in which only one or two pregnancies actually had the condition in question.”

Pro-life advocate Alison Centofante grieves the lives that have been lost to abortion as a reaction to these false positives. 

In America, NIPTs are fairly common, with about a third of women voluntarily opting to undergo the testing. Often, women are advised to abort if given a poor prenatal diagnosis through prenatal testing.

“For these tests to be wrong, and for doctors to be advising to abort because of these tests, is terrible,” Centofante shared on her Instagram stories.

Currently pregnant with her second child, she warned: “If you’re pregnant, or considering it, just be aware that you could get a false positive with these results.”