The CancerSEEK test looks for mutations in 16 genes that regularly arise in cancer and eight proteins that are often released.
It was trialled on 1,005 patients with cancers in the ovary, liver, stomach, pancreas, oesophagus, colon, lung or breast that had not yet spread to other tissues.
Overall, the test found 70% of the cancers.
Dr Cristian Tomasetti, from Johns Hopkins University School of Medicine, told the BBC: “This field of early detection is critical.
“I think this can have an enormous impact on cancer mortality.”
The CancerSEEK test, reported in the journal Science, is novel because it hunts for both the mutated DNA and the proteins.
Increasing the number of mutations and proteins being analysed would allow it to test for a wider range of cancers.
Dr Gert Attard, team leader in the Centre for Evolution and Cancer at the Institute of Cancer Research, London, and consultant medical oncologist at the Royal Marsden NHS Foundation Trust, told the BBC: “This is of massive potential.
“I’m enormously excited. This is the Holy Grail – a blood test to diagnose cancer without all the other procedures like scans or colonoscopy.”
He said “we’re very close” to using blood tests to screen for cancer as “we have the technology”.