The test could now become available on the NHS by 2017, and potentially save the lives of 300 babies a year.
Medics tested 2,049 pregnant women in the trial, and the results are published today in the American Journal of Obstetrics and Gynaecology.
Currently, all pregnant women are screened at their 12 week scan, where a 'nuchal translucency' test is carried out. Of every 10,000 women tested, 527 will then be advised to have further tests - an invasive procedure which carries a 1 in 100 chance of bringing on a miscarriage.
Professor Kypros Nicolaides, of the Harris Birthright Research Centre for Foetal Medicine at King's College Hospital, London told the Telegraph that the new test was 'highly accurate for routine screening of all pregnant women, not just those deemed high risk'.
He said he expected the new test will be adopted by the NHS in five years. Professor Nicolaides said the new blood test would reduce the numbers of women who need invasive screening for Down's to 10 in 10,000.
"For every 10,000 women, 30 carry foetuses with Downs," he said, "The current process picks up 27 but miss the other three. With the new test, we will pick up all 30."
The test - called the Harmony Prenatal Test -is being developed by US company Ariosa Diagnostics.
Prof Nicolaides said he would be making the blood test available free to mums-to-be in the UK who were willing to be part of the the ongoing trials.
A spokesman for the Department for Health said it would 'keep all evidence for pre-natal screening under review and make recommendations in light of any new findings'.
More on Parentdish: What are antenatal tests and what is available to you?
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