BLOOD TEST COULD TRIM HEALTH COSTS

Researchers said a blood test combination designed to detect fetuses with Down syndrome could eliminate most amniocentesis tests for women over 35 and save millions of dollars in health-care costs.

The proposal, outlined in Thursday's New England Journal of Medicine by researchers in California and Maine, could provide an alternative to the current practice of offering amniocentesis or a newer screening technique known as chorionic villus sampling to all pregnant women over 35.Chorionic villus sampling detects virtually every case of Down's syndrome, but the test itself can trigger a miscarriage, as can amniocentesis.

A research team led by Dr James Haddow of the Foundation for Blood Research in Scarborough, Maine, tested the blood of 5,385 women for three chemicals, the levels of which are known to be related to the risk of having a child with Down syndrome.

The researchers calculated that if those tests alone were used to determine whether amniocentesis is done, 89 percent of Down syndrome cases would still be identified while 11 percent would be missed.

Instead of all healthy women facing a small risk of miscarriage from amniocentesis or chorionic villus sampling, only about one in four would be advised to undergo genetic testing during their second trimester.

The Haddow team estimated that by failing to detect 11 percent of cases of Down syndrome, society would prevent the miscarriage of 14,000 otherwise healthy fetuses. It would also produce 320 more children with Down syndrome and save an estimated $250 million in health-care costs nationwide.

"One argument against replacing current practice with a policy based on biochemical screening is that the latter will detect only 9 out of every 10 cases of Down syndrome," whereas routine amniocentesis is about 100 percent successful in detecting these cases, Haddow and his colleagues said.

"This fact needs to be weighed, however, against the large reduction in the number of women requiring amniocentesis that can be achieved with biochemical screening and, as a consequence, the reduction" in miscarriages that would result from fewer genetic tests, they said.