The Galleri Blood Test for Multiple Cancers: What to Know
The Galleri blood test can detect more than 50 different types of cancer. It looks for patterns in circulating DNA that can signal the presence of cancer in your body. Its accuracy can vary by cancer type.
A multicancer early detection (MCED) test is a type of test that uses a blood sample to identify several different types of cancer. It works by looking for proteins or genetic factors that are related to cancer.
The Galleri test is a type of MCED test that your doctor can order. It analyzes a blood sample for patterns in DNA that can signal the presence of cancer in your body.
This article will take a closer look at what’s known about the Galleri test so far. This includes how accurate it is, its associated risks, and whether or not it’s covered by insurance.
The Galleri test is an MCED test that’s produced by the company GRAIL. It can be used to identify cancer in asymptomatic adults who are at a higher risk of cancer, such as people ages 50 and over.
How does the Galleri test work?
The sample needed for the Galleri test is collected by a simple blood draw. This involves collecting a small amount of blood from a vein in your arm.
This sample is then sent to a lab where DNA sequencing and machine learning are used to analyze cell-free DNA. Cell-free DNA is a type of DNA that’s been released from cells and is present in your blood.
There are differences in the cell-free DNA of healthy cells and cancer cells. The Galleri test looks for specific patterns of changes in cell-free DNA that may signal that cancer is present. It also aims to identify where the cancer started.
If a cancer-related signal is detected, additional tests can be done to help confirm the diagnosis.
What types of cancer can the Galleri test find?
The Galleri test can identify more than 50 types of cancer, including some of the most common cancer types , such as cancers of the:
The test can also identify cancers that are much less common and that doctors don’t typically screen for. A couple of examples include ampullary cancer and certain types of soft tissue sarcoma.
What’s unknown about the Galleri test?
One of the big unknowns about the Galleri test is whether or not using it as a part of cancer screening will help to improve people’s outcomes and save lives. Clinical trials are currently underway to look into this.
The largest of these clinical trials is the NHS-Galleri trial, which is being done in the United Kingdom. It aims to see if using the Galleri test with established cancer screening methods can help to find and treat cancers earlier.
About 140,000 people with no history of cancer in the past 3 years volunteered to take part in the trial. Everyone in the trial will have three blood tests over 2 years. Half of the participants will have their samples analyzed using Galleri.
The National Cancer Institute (NCI) is also studying the benefits of MCED tests such as Galleri in preventing cancer deaths. In 2024, it aims to start enrolling 24,000 healthy people in a pilot study. If MCED tests are found to be useful, a larger study of up to 225,000 people will be set up.
A 2021 validation study looked into the accuracy of the Galleri test. It included 2,823 people with a known diagnosis of cancer and 1,254 healthy people.
The study found that the Galleri test had a 99.5% specificity. This means that it was very accurate for determining when a person didn’t have cancer-related signals in their sample, making false-positive results very unlikely.
While the sensitivity of the test varied greatly by cancer type, its overall sensitivity was 51.5%. This means that it correctly identified a little more than half of people with cancer-related signals in their sample.
The test missed cancer-related signals in the remaining percentage of people. This means that these individuals received a false-negative result.
The sensitivity of the Galleri test also increased as cancer stage increased. That means that it was more likely to identify cancer-related signals in people with more advanced cancers.
Lastly, in individuals who received a positive result and had cancer, the Galleri test correctly identified the origin site of the cancer in 88.7% of people.
Some types of cancer have recommended screening tests. For example, the American Cancer Society (ACS) recommends that people at average risk of colorectal cancer start getting a cancer screening at age 45 using stool- or visual-based tests.
If the use of the Galleri test becomes more widespread, it isn’t meant to replace these standard cancer screening tests. Instead, it’s meant to supplement these tests to help find cancers in their early stages when they’re easier to treat.
There are a few potential risks of the Galleri test that are important to keep in mind:
- The Galleri test doesn’t detect all types of cancer. This means that you could get a negative result and still have a type of cancer that the test can’t find.
- The Galleri test isn’t always accurate at finding cancer-related signals, and it can give false-negative results when you actually have cancer. This can give you a false sense of security and also delay vital treatments.
- Although a lot less common, it’s also possible for the Galleri test to give false-positive results. Not only can this lead to increased anxiety, but it also means that you could end up getting additional diagnostic tests when you don’t actually have cancer.
If you’re interested in having the Galleri test, talk with a doctor about it. They can help you understand whether you’d be a good candidate for the test and also provide you with information about the different benefits and risks associated with this test.
The Galleri test was introduced at a cost of $949 . According to GRAIL, the manufacturers of the Galleri test, some individual employers may cover some or all of the cost of testing.
Both the ACS and the NCI note that most types of insurance don’t typically cover the Galleri test. This means that you’ll likely have to pay some or all of the cost of the test out of pocket.
Medicare currently doesn’t cover the cost of the Galleri test either, but a bill on this topic was introduced into Congress in 2021. If enacted into law, it would provide Medicare coverage for MCED tests such as the Galleri test.
At this time, no MCED tests have been approved by the Food and Drug Administration (FDA). This includes the Galleri test.
Instead, the Galleri test is available under a Clinical Laboratory Improvement Amendments (CLIA) waiver, since the actual testing of the sample is done in a central laboratory regulated by CLIA. CLIA is a federal program that sets and ensures quality standards for clinical laboratory testing.
The Galleri test was given a Breakthrough Device designation by the FDA in 2019.
The FDA’s Breakthrough Devices Program designates medical devices that may increase the effectiveness of the diagnosis or treatment of life-threatening diseases. The goal is to provide timely access to these devices while accelerating their development.
The Galleri test is a blood test that can detect more than 50 different types of cancer. It looks for patterns in circulating DNA that can signal the presence of cancer in your body.
While initial studies have been promising, the Galleri test needs to be studied in further clinical trials. These trials can help determine if the Galleri test improves people’s outcomes and saves lives when used with standard screening tests.
If you’re at an increased risk of cancer, a doctor can order the Galleri test. It’s important to talk with a doctor about the benefits and risks of this test to help determine if the Galleri test is a good fit for you.
Last medically reviewed on March 17, 2023