VARIATION IN BIOCHEMICAL SCREENING FOR DOWNS-SYNDROME IN THE UNITED-KINGDOM

A questionnaire survey was undertaken of all 73 laboratories performin g Down's syndrome screening in 1995. An estimated 352,000 tests were p erformed representing 47% of maternities. Three-quarters of these test s have ultrasound dating information at the time of testing. The major ity of laboratories (70%) commenced screening at 15 weeks of gestation or later, and there was considerable variation in the upper limit of screening (17 to 24 weeks). Eighty-six percent of laboratories screene d all women regardless of age. The reported Down's syndrome risk was b ased on term in 85% of laboratories. There was an inconsistent approac h to determining and reporting high risk for trisomy 18 (Edwards' synd rome): 5% reported risks on report forms and 42% notified the clinicia ns if the risk was considered to be raised.