Frequently asked questions

You can ask for the collection of information about your health from the NHS to stop at any time, and you do not have to give a reason why. However, information about you that has already been collected will be kept. 

If you would like to stop this data collection, or if you want to leave the trial, please contact the trial team.

You can change your mind about your samples being stored for future research, and you do not have to give a reason why. If you do not want your samples to be stored for future research, please contact the trial team. Your stored samples will then be destroyed.

You do not need to contact the trial team if you move house or leave England after your last trial appointment.

Once information has been collected from all the trial participants, it will be analysed to see if using the test alongside existing cancer screening can help the NHS to find cancer early. 

The final results of the trial will be checked by other researchers to make sure the results make sense. This is how high-quality research is done – it always needs to be checked by other researchers. 

Once the results of the trial are available, these will be shared publicly. Often this is in a science journal, press release, or on the trial website. Results are likely to be ready in 2026 but may take longer.

The NHS has been considering whether to offer up to 1 million Galleri tests in England as part of a pilot to screen for cancer, alongside existing national cancer screening programmes. NHS England has decided to wait to see the final results from the NHS-Galleri trial before deciding whether to run a pilot programme.

A trial is a type of research study that aims to understand whether a new treatment or test works better than other approaches that are already being used. 

The NHS-Galleri trial is not accepting new participants at this time — registration is closed.

One of the questions researchers want to answer is how often people should be tested with the Galleri test to help the NHS find cancer early. Looking at your blood samples spaced about 12 months apart will help researchers to answer this question.

Testing blood samples after the second and third appointments may find more cancers at an early stage.

By attending your appointments you have helped research to understand how the NHS might be able to offer the test to people in the future.

When you took part in the trial, you were asked to give a number of blood samples. Giving blood samples is generally safe but there are some possible side effects including:

• discomfort
• lightheadedness
• infection

If the test detects a cancer signal, you could experience anxiety or distress. Like all screening tests, the Galleri test is not perfect and can give a wrong result. If the test detects a cancer signal and no cancer is found by the doctor, you may have had further tests that were unnecessary. Those further tests can have their own risks, such as radiation from scans, that you should discuss with your doctor before having them.

The trial team try to make sure people who take part in the NHS-Galleri trial have a good trial experience. 

The trial is taking place in the following eight Cancer Alliance areas in England:

• Cheshire and Merseyside
• East of England (North)
• Greater Manchester
• Kent and Medway
• East Midlands
• West Midlands
• Northern
• South East London

During and after the trial, the test and control groups will be compared. One of the results that will be looked at is if cancers are found at an earlier stage in the test group than in the control group.

Additional information will be recorded about diagnostic tests and cancer treatments given.

People in the control group will have their blood samples stored. These samples may be tested with the Galleri test in the future. If you are in the control group, you will not get any test results if your samples are tested in the future, not even after the trial is finished.

One of the questions researchers want to answer is how often people should be tested with the Galleri test to help the NHS find cancer early. Looking at your blood samples spaced about 12 months apart will help researchers to answer this question.

Testing blood samples after the second and third appointments may find more cancers at an early stage.

About half the people who have a cancer signal detected will be found to have cancer after further tests in the NHS, and the other half will not.

If the Galleri test finds a cancer signal, but no cancer is found after further tests, please continue to attend any cancer screening appointments you are invited to and visit your GP if you experience any symptoms that are new or unusual for you.

If you are in the control group, or if no cancer signal is found, you will have been sent a thank you letter to confirm that your blood sample was safely received by the lab. This normally takes around 30 days to arrive after you have had your blood sample taken, but may sometimes take longer. 

You will not know from the letter if your blood sample has been tested or not. It is therefore important that you continue to attend any cancer screening appointments you are invited to and visit your GP if you experience any symptoms that are new or unusual for you.

The control group samples may be tested with the Galleri test in the future to help the trial team understand any differences between what happens to people in the test group and the control group. If you are in the control group, you will not get any test results from the trial, not even after the trial is finished. You will be asked if your samples can be stored and tested after the trial ends to help with other research to improve how well the test works.

You have been asked to give permission for the trial team to share and receive information about your health with the health professionals who are involved in your care. This could include your GP. If the Galleri test finds a cancer signal in your blood, your GP will be told about this. 

If you have or are planning to purchase private health insurance, life insurance, or travel insurance, you should check with your provider if taking part in this trial affects your ability to make claims in the future.

If you are found to have cancer by taking part in the study, you may have to provide this information on an insurance application if you are asked for it.

In the event of loss of mental capacity, such as if something happened to you that meant you no longer fully understood what the trial was or why you were part of it, you may be removed from the trial. However, we would continue to use any samples or information that had already been collected about you until that point. Please contact the trial team.

Taking part in the trial is completely voluntary. You can leave the trial (withdraw) at any time. You do not need to give a reason why and your normal medical treatment will not be affected. If you no longer wish to take part in the trial, please contact the trial team.

The Galleri test is not currently available on the NHS or to buy in the UK. The test is only available in England as part of clinical trials.