Can a blood test detect cancer? What the NHS-Galleri trial found
Short answer: not reliably yet. The NHS-Galleri trial tested a multi-cancer early detection blood test in more than 140,000 people in England. Results presented in May 2026 showed it found more cancers through screening and fewer at the most advanced stage, but it did not meet its main goal, and it is not yet known whether it saves lives. It is not part of routine NHS screening.
What the trial did
Adults aged 50 to 77 without cancer symptoms had a blood test once a year for three years, alongside their usual NHS screening. Half had their samples tested with the Galleri test. The test looks for fragments of DNA in the blood that may come from cancer cells, and predicts where in the body the signal comes from.
What the results showed
More cancers were found through screening in the group that had the test
Fewer cancers were diagnosed at stage 4, and fewer were found in emergencies such as A&E
The trial did not meet its main goal of reducing stage 3 and stage 4 cancers combined
Longer follow-up is needed to show whether it reduces deaths from cancer
What about other cancer blood tests?
Tumour markers such as PSA, CA125 and CEA are not general screening tests. They can be raised without cancer and normal when cancer is present. They are mainly used to investigate specific symptoms or to monitor a known cancer, so a clinician should help you decide whether one is useful.
Genetic tests show risk, not cancer
Genetic tests such as the hereditary breast and ovarian cancer risk test look for inherited changes that raise your risk. They cannot tell you whether you have cancer now.
Keep up with NHS screening
NHS bowel, breast and cervical screening are proven to save lives. Bowel screening uses a home FIT kit; you can also book a FIT test privately. See your GP about unexplained weight loss, a lump, unusual bleeding, or a change that does not go away, whatever any test has shown.
Frequently asked questions
Does a normal blood test mean I do not have cancer?
No. Routine blood tests are often normal in early cancer. Symptoms always need checking.
Should I have a CA125 test?
In the UK, CA125 is used for women with symptoms such as persistent bloating, feeling full quickly or pelvic pain. Discuss your symptoms with your GP first.
Is a genetic cancer risk test worth having?
It is most useful if several close relatives have had cancer, especially at a young age. If that applies to you, ask your GP about NHS genetic services.
Sources
King's College London: first results from the NHS-Galleri trial (May 2026)
UCL: first results from the NHS-Galleri trial announced (June 2026)
Cancer Research UK: Galleri multi-cancer early detection blood test
NICE guideline CG122: ovarian cancer, recognition and initial management
Related reading
Clinically reviewed by Zak Toon, ACP, on 15 October 2026.
This article is general information based on UK guidance. It is not personal medical advice. If you are worried about your health or have symptoms, speak to your GP or call 111.
