News and Analysis

Report: Common Prenatal Genetic Tests Produce Incorrect Results 85% Of The Time
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A stunning new report from The New York Times found that certain types of prenatal tests used to identify rare genetic disorders are inaccurate up to 85% of the time. 

The tests utilize a relatively new technology that use a small sample of maternal blood to screen for chromosomal abnormalities in the fetus.

In the case of Down’s syndrome, the tests are fairly accurate, but the tests also claim to identify other, rarer genetic disorders that result from gene microdeletions, which are caused by a tiny missing portion of a chromosome.

The Times looked at five specific popular microdeletion tests. They found that the test for DiGeorge syndrome, which is associated with heart defects, is inaccurate 81% of the time when the result is positive. The four other tests had drastically inflated positive rates, as well. One was 80% inaccurate, another was 84%, 86%, and one had a 93% chance that a positive result was incorrect.

Families often make serious decisions based on the results of such testing. 

The Times noted: 

One [geneticist] described a case in which the follow-up testing revealed the fetus was healthy. But by the time the results came, the patient had already ended her pregnancy.

The impact such testing can have on the rate of abortions has the potential to be monumental.

The percentage of babies with Down syndrome who are aborted isn’t clear but the number of babies born with the condition has gone down dramatically around the world. A study from late 2020 showed that babies born every year with Down’s dropped by an average of 54% in Europe due to the rise in prenatal testing. A study from 2016 with the same group discovered that 33% fewer babies with Down syndrome were born each year in the U.S.

Other tests for genetic disorders also lead to women getting abortions, too, especially because many of them are carried out very early in pregnancy. Many women make their decision based on these tests alone. A study from 2014 showed that 6% of women who received a positive test result got an abortion without getting an additional test to be sure it was right. 

“That same year The Boston Globe quoted a doctor describing three terminations following unconfirmed positive results,” the Times reported.

These kinds of tests are not regulated by the U.S. Food and Drug Administration, which some say would impact at least how the tests are advertised to prospective parents, since many of the companies claim their results are “highly accurate” and provide “peace of mind.” 

The Times noted that it “reviewed 17 patient and doctor brochures from eight of the testing companies, including Natera, Labcorp, Quest and smaller competitors. Ten of the brochures never mention that a false positive can happen. Only one mentioned how often each test gets positive results wrong.”

“The F.D.A. considered regulating these tests a decade ago, but backed away,” the outlet added. 

The size of the business possibilities could also be massive. The Times noted that companies started creating their own tests after witnessing success in the field. “Today, analyst estimates of the market’s size range from $600 million into the billions, and the number of women taking these tests is expected to double by 2025,” the outlet added.

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The Daily Wire   >  Read   >  Report: Common Prenatal Genetic Tests Produce Incorrect Results 85% Of The Time