What the trial found
The first results from the NHS-Galleri trial are now available. These results help to understand:
- If the Galleri® blood test can help find cancer earlier
- If the test changes how people are diagnosed
- If the test is accurate
You can read a summary of the first results from the trial on this page.
Detailed trial results available
The first trial results have been shared with researchers at a scientific conference. If you’d like to learn more, you can read our news update on the conference.
To get the trial results, the researchers measured the number of cancers found in people who had the blood test (test group) and the number of cancers found in people who did not have the test (control group). They looked at cancers diagnosed between the first appointment and up to 18 months after the third appointment.
The researchers looked at cancers diagnosed between the first appointment and up to 18 months after the third appointment.
The researchers then compared the number of cancers found in each group in different ways to understand the effect of the blood test.
You will not be told if you are in the test or the control group, not even after the trial has finished. If people know which group they are in, it might alter the way they behave about their health. This could make the research results less clear or reliable.
Finding cancer earlier
The aim of the NHS-Galleri trial is to see if using the blood test could help the NHS find cancer early. Finding cancer early usually means people have more treatment options and better outcomes.
To measure this, the researchers looked at the number of late-stage cancers overall (stage 3 and 4 together), comparing the number diagnosed in the test group with the number in the control group. This was the main goal of the trial. They also measured cancers diagnosed at other stages.
What is cancer stage?
Cancer stage describes how big a cancer is and if it has spread. It helps doctors understand if a cancer is early in its development or more advanced. Stage 1 is the earliest stage, and stage 4 is the most advanced.
The researchers started by looking at a group of 12 types of cancer that can grow quickly and are often found at a late stage. The researchers then looked at all cancers together.
The trial results showed:
No difference in late-stage cancer overall
Fewer people diagnosed with the most advanced cancers
More people diagnosed with early stage cancers
There was no difference between the test group and the control group in the number of people diagnosed with late-stage cancer overall, when stage 3 and stage 4 cancers were looked at together. This means that the trial did not meet its main goal. Fewer people were diagnosed with the most advanced cancers among those who had the test, when stage 4 cancers were looked at on their own. There were more early stage cancers (stage 1 and 2) in the test group.
The 12 types of cancer are:
- Anus (where the bowel connects to the outside of the body)
- Bladder
- Bowel
- Head and neck
- Liver and bile duct
- Lung
- Lymphoma (a type of blood cancer)
- Oesophagus (food pipe)
- Ovary
- Pancreas
- Plasma cell neoplasm (another type of blood cancer)
- Stomach
These cancer types can grow quickly and are often found at a late stage.
How cancers were diagnosed
Another aim of the trial was to look at how people who got cancer were diagnosed.
In the NHS, people can be diagnosed with cancer in different ways. For example, someone might be diagnosed after an NHS screening test, like a mammogram, after a visit to a GP, or after a trip to A&E.
Cancers found through screening are usually diagnosed before someone has symptoms and as part of routine NHS processes. Cancers diagnosed in emergency situations are often found when someone becomes unwell and needs urgent care.
The trial results showed:
More people diagnosed after screening
Fewer people diagnosed in an emergency
In the group who had the test, more people were diagnosed with cancer after screening and fewer diagnosed in an emergency situation.
How accurate the test was
The trial also measured how accurate the test was at detecting cancer. To measure this, the researchers looked at only people who had the blood test (test group).
The researchers looked at how well the test finds cancer in people who do have the disease, how well it avoids false alarms in people who do not have cancer, and how often a positive result means that the person does have cancer.
The trial results showed:
Around a third of people who had cancer got a positive test result
Nearly everyone who did not have cancer got a negative test result
Around half the people who had a positive test result were diagnosed with cancer
Around a third of people who had cancer got a cancer signal detected (‘positive’) test result. Nearly everyone who did not have cancer got a no cancer signal detected (‘negative’) test result. This means that the test gave a false alarm less than 0.5% of the time.
Around one in 100 people had a positive test result. Around half the people who had a positive result were diagnosed with cancer.
What happens next
A lot has been learned from the NHS-Galleri trial about how well the blood test works for cancer screening in the NHS. A lot of other information has been learned about cancer biology and multi-cancer screening.
Thank you for taking part in the trial. The trial and everything that is being learned from it would not be possible without your support.
More results will be available in the coming months and years, as researchers carry on collecting and analysing data from the trial. Some of the other things they are looking at are if people who have a cancer signal detected result feel anxious, if the test is good value for money and if using the test might help reduce cancer deaths.
The NHS and other health organisations will review the results of the trial in detail to understand how this type of test could be used in the future.
Review status
Last updated: 30 May 2026