Galleri: The blood test with 'the ability to transform cancer care forever'

ITV News' Health and Science Correspondent Martin Stew reports on the potentially transformative blood test being trialled

We all know the earlier you catch cancer, the better your chances of getting successful treatment.

The idea of one blood test which can identify 50 different types of the disease before any symptoms have even started is a tantalising prospect.

The Galleri test, made by US company Grail, is already being trialled on 142,000 people in England. It will publish its results next spring. 

The chief executive of the NHS has described the test as having “the ability to transform cancer care forever”.

Amanda Pritchard said it would be especially useful for “the types that often don’t show symptoms until a later stage, when they can be much harder to treat.”

There are now plans to roll it out to one million people next summer.

It’s hoped amongst a group of that size, it could detect up to 5,000 cancers a year.

How does the Galleri test work?

All cells in your body, including cancer cells, release fragments of DNA into your bloodstream.

DNA from cancer cells are different from the DNA of healthy cells.

If the test detects cancer, it is able to look closer at the DNA and pinpoint where in the body it is likely to have come from.

It can’t detect all cancers and you can get both false positives and false negatives - so it is an additional tool, not a full replacement for current tests.

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