[Comparison between age-dependent (Wald alpha program) and age-independent (Ulm index) analysis program for prenatal detection of Down's syndrome with serum markers].

An age-dependent analytic program (Alpha-Software from Wald) was compared to an age-independent Index (Ulm-Index) in order to determine effectivity of detection in prenatal screening for Down's Syndrome in 7060 pregnant women. The rate of accuracy was similar in both analytic programs (6 from 7), but, the rate of false-positive results was twice as high using the Ulm-Index (14.7 versus 7.7%). The higher rate of amniocentesis necessary using the age-independent Ulm-Index apparently does not justify this method for prenatal screening of Down's Syndrome.