A 10-minute cancer test that can be taken at home using just a drop of saliva is being developed by scientists.
David Wong, a professor of oncology at the University of California, Los Angeles, says it is possible to detect tumour DNA in bodily fluids by means of a "liquid biopsy".
The test looks for genetic mutations in blood plasma that are consistent with a tumour.
The saliva test is 100 per cent accurate and is so simple that it could be carried out at a pharmacy or a dental clinic, or by someone on their own, he claims. Currently scientists can only use blood tests to detect cancer if they have taken a biopsy and sequenced a tumour to discover which genetic signature to look for.
This can be used to monitor cancer spread, but not for an initial test, and it can throw up false positive results.
Prof Wong's test has shown that a drop of saliva contains enough data to give a definitive diagnosis as soon as a tumour develops, he said.
The test is non-invasive, costs around £15 and will enter full clinical trials with lung cancer patients later this year.
Prof Wong is expecting the test to be approved within two years by the Food and Drug Administration in America. He is hoping it will be available in Britain by the end of the decade.
"Down the road it might be possible to test for multiple cancers at the same time," Prof Wong told annual meeting of the American Association for the Advancement of Science in Washington.