The trial followed 25,000 adults from the US and Canada over a year, with nearly one in 100 getting a positive result. For 62% of these cases, cancer was later confirmed.
Lead researcher Dr Nima Nabavizadeh, associate professor of radiation medicine at Oregon Health & Science University, said the data showed that the test could "fundamentally change" their approach to cancer screening.
He explained that it could help detect many types of cancer "earlier, when the chance of successful treatment or even cure are the greatest".
The test correctly ruled out cancer in over 99% of those who tested negative.
When combined with breast, bowel, lung and cervical screening it increased the number of cancers detected overall seven-fold.
Crucially, three-quarters of cancers detected were those which have no screening programme such as ovarian, liver, stomach, bladder and pancreatic cancer.
The blood test correctly identified the origin of the cancer in nine out of 10 cases.
These impressive results suggest the blood test could eventually have a major role to play in diagnosing cancer earlier.
But scientists not involved in the research say more evidence is needed to show whether the blood test reduces deaths from cancer.
Clare Turnbull, professor of translational cancer genetics at The Institute of Cancer Research, London, said: "Data from randomised studies, with mortality as an endpoint, will be absolutely essential to establish whether seemingly earlier-stage detection by Galleri translates into benefits in mortality."
The topline results are to be released at the European Society for Medical Oncology congress in Berlin on Saturday, but the full details have yet to be published in a peer-reviewed journal.
Much will depend on the results of a three-year trial involving 140,000 NHS patients in England, which will be published next year.
The NHS has previously said that if the results are successful, it would extend the tests to a further one million people.
