Down's test 'more accurate'

A more accurate Down's syndrome test is possible

A combination of blood test and ultrasound can more accurately predict Down's syndrome, say experts - but it will cost mothers £120.

The so-called "integrated test" has been developed by researchers at the Wolfson Institute of Preventive Medicine in east London.

They claim it can predict the birth defect with 85% accuracy - an improvement on current tests.

It also has a lower "false positive" rate, meaning that fewer women will be told their baby could have Down's when in fact it is normal.

Fewer mothers-to-be would then have to undergo further tests, particularly amniocentesis, which can trigger miscarriage.

Professor Nicholas Wald: 'Test will benefit women'

However, it has not yet been approved for use on the NHS, and will only be available from the institute at a cost of £120.

Late result

In addition, the test, which checks levels of key proteins in the blood, can only be taken at the 20 week mark in pregnancy, according to a paper about it published in the New England Journal of Medicine in August.

This means that by the time the results are known, the pregnancy will be more advanced.

Although a suspected Down's foetus can be legally aborted at any point of the pregnancy, a woman opting for termination may have to undergo a more traumatic procedure.

US commentators said that it was unlikely that it would become popular there.

However, Professor Nicholas Wald, from the University of London, said the test was of benefit.

He said: "It's a more effective test - it will identify Down's more effectively and do so at a lower false positive.

"There will be less women who have to go on and have amniocentesis, which carries a risk to the baby."

Approximately one in every 650 foetuses is at risk from Down's syndrome.

The risk increases with the age of the mother.