A new blood test designed to detect more than 50 types of cancer is now available, but experts are on the fence on how helpful it is and whether it is worth the hefty price tag. The Galleri $949 liquid biopsy can screen for cancers by looking for a shared cancer signal in DNA shed by tumors in the bloodstream.

According to The Wall Street Journal, more than 130,000 of the prescription-only tests have been sold since Galleri became available in 2021. It’s one of the tools patients who can afford such testing can request to find out more about their health, alongside full-body MRI scanning and biological age testing.

But some experts warn that there is no research on how this test can prevent cancer deaths and are concerned about the risk of getting false-positive or negative results. One study found that more than half the people who got a positive test result didn’t have cancer.

However, proponents say that the promise of early cancer detection outweighs the risks, and that these tests will improve both cancer detection and public health. They add that a positive result is not a diagnosis but an invitation for further evaluation by a healthcare practitioner.

“We still lose 600,000 people a year due to cancer in the U.S., which really speaks to the unmet need and the urgency about this new technology,” said Dr. Eric Klein, a scientist at Grail, the company that manufactures Galleri.

Grail says that the Galleri test, one of a few commercially available tests known as multicancer early detection (MCED), is meant as a supplement and doesn’t replace recommended cancer screenings. The tests aren’t covered by most insurance plans and none of the MCEDs are approved by the Food and Drug Administration or recommended by the U.S. Preventive Services Task Force.

Grail suggests that the test is suited for people over the age of 50 with an elevated risk of cancer or who have genetic risk factors. It’s not recommended for people who are pregnant, under the age of 21 or undergoing active cancer treatment, says The Wall Street Journal.

A recently published company-funded study showed that the Galleri test returned a false positive in less than 1% of all people screened. Among those who got positive results, 62% did not have cancer. Dr. Deborah Schrag, lead author of that study and chair of the department of medicine at Memorial Sloan Kettering Cancer Center, suggests waiting for the results of the NHS-Galleri trial that will include 140,000 volunteers ages 50 to 77 years to see if the Galleri test, alongside existing cancer screening, can help find cancer early when it’s usually easier to treat.

“We’re getting ahead of ourselves on the evidence,” she says. The National Cancer Institute plans to launch a study in 2024 assessing whether MCED tests given to healthy patients can reduce cancer-related deaths. While Grail says it is working with insurance companies to offer coverage, many practitioners say that both the lack of evidence and the high price tag of the test are deterrents in their practices.

According to Healthline, the Galleri test doesn’t detect all types of cancer. And the test isn’t always accurate at finding cancer-related signals, so it could give a false-negative result when you actually have cancer. This can give you a false sense of security and could lead to a delay in vital treatment.

And although false-positive results are rare, they can lead to anxiety and getting more diagnostic tests when you really don’t have cancer. Experts suggest talking with your doctor to see it the Galleri test is right for you.