These Tests Could Have "False Results," FDA Says in New Warning

You might want to reconsider using this blood test.

We're all striving to maintain our health and general wellbeing, which many of us do by making healthy choices, heading to the gym a few times a week, and checking in with our doctors annually. One of the ways healthcare providers keep tabs on our health is through blood tests—and while that's not the most pleasant part of a check-up, it's essential. Not only can these tests check for different diseases and conditions, but they can also ensure your organs are functioning properly and determine whether treatments are effective, the National Heart, Lung, and Blood Institute says. However, these tests are not always what they seem, and the U.S. Food and Drug Administration (FDA) just issued a warning about one kind of test in particular. Read on to learn more about the blood test you might want to reconsider.

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Blood tests have multiple uses, but some approaches have sparked debate and controversy.

Doctors look at a test vile in a lab

Blood tests play a pivotal role in maintaining your overall health, and can sometimes alert us to conditions we didn't even know we had. In fact, actor Ben Stiller made headlines after learning that he had prostate cancer thanks to a prostate-specific antigen (PSA) test. Stiller called the test "controversial," as its use is debated among medical professionals.

And that's not the only test that has been a hot topic of discussion. Fans of Hulu's The Dropout will recognize the name Theranos, a company that claimed to be able to perform hundreds of tests with just a single drop of blood. Headed by its now-infamous CEO Elizabeth Holmes, the company's claims ended up being false and Theranos was shut down amid fraud allegations. Now, additional commercialized blood tests have risen in popularity, but there are lingering questions about reliability.

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Certain types of blood tests could actually produce "false results."

pregnant woman surrounded by mosquitoes

When it comes to keeping children safe, parents are committed to going the extra mile. Expectant parents, however, will want to be cautious when using non-invasive prenatal screening (NIPS) tests, which are also called cell-free DNA tests or non-invasive prenatal tests (NIPT), according to a warning issued by the FDA on April 19.

These tests analyze a sample of blood from a pregnant person, looking for "signs of genetic abnormalities in a fetus," the agency said. But NIPS tests are screening tests rather than diagnostic tests, which means they provide information only about the risk of a genetic abnormality. To confirm whether these results are accurate and whether or not the fetus actually has this abnormality, additional testing may be required.

The FDA issued the warning due to the tests being widely used.

A closeup of a doctor's hand reaching for a blood sample in a vial

As The Verge reported, these tests are considered "lab-developed tests," which are not subject to review by the FDA before being sold and advertised by companies. Parents might not be aware of the limitations of these tests, and as many seek confirmation that their baby will be born happy and healthy, the use of NIPS tests has increased as of late, the FDA said.

"While genetic non-invasive prenatal screening tests are widely used today, these tests have not been reviewed by the FDA and may be making claims about their performance and use that are not based on sound science," Jeff Shuren, MD, JD, director of the FDA's Center for Devices and Radiological Health, said in the warning.

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If you are going to use an NIPS or NIPT test, the FDA advises doing this first.

pregnant woman sitting and consulting doctor
Syda Productions / Shutterstock

These tests claim to provide "peace of mind," but they are particularly limited when screening for rarer conditions, which often leads to a false positive (meaning the fetus is not actually affected), the FDA said. Tests can also cause confusion for parents by accurately detecting a chromosomal abnormality, which may only be present in the placenta and not in the fetus. Earlier this year, The New York Times looked into these prenatal blood tests, noting that when testing for rare disorders, like Cri-du-chat syndrome and Wolf-Hirschhorn syndrome, results were wrong 80 percent or more of the time.

The FDA said it is aware of these media reports and "critical health care decisions" being made due to these test results. "Without proper understanding of how these tests should be used, people may make inappropriate health care decisions regarding their pregnancy," Shuren said. "We strongly urge patients to discuss the benefits and risks of these tests with a genetic counselor or other health care provider prior to making decisions based on the results of these tests."

The FDA is considering taking further action on these tests.


These tests are considered medical devices under the Federal Food, Drug, and Cosmetic Act, and the policy of "enforcement discretion" has not changed since 1976 when the Medical Device Amendments were added. However, the agency is looking to "establish a modern regulatory framework" for all testing, according to the warning statement. The agency also noted it will continue to monitor these safety issues, as well as the use of NIPS tests.

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Abby Reinhard
Abby Reinhard is an Associate Editor at Best Life, covering daily news and keeping readers up to date on national parks, scientific studies, and the best pet advice. Read more
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