[The significance of screening tests for aneuploidies in populations at low and high maternal-age-related risk]. / Il significato dei test di screening per le aneuploidie in popolazione a basso e alto rischio per età.

AIM: The aim of this study was to evaluate the validity of the triple test and the screen test in maternal populations at low and high maternal-age-related risk for fetal aneuploidy. METHODS: As a whole, 9,680 pregnant women at low risk and 627 at high risk underwent the triple test; 2,780 pregnant women at low risk and 408 at high risk underwent the screen or combined test; sensitivity, specificity, false positives and detection rate were compared between populations using Student's t-test. RESULTS: The triple test showed a detection rate of 75% in the low and 83.3% in the high risk population with a difference (P<0.003) for detection of trisomies 21 and 18 between the 2 populations; the screen test had a detection rates of 100% and 90% in the 2 populations, respectively, with a difference (P<0.005) between the 2 tests. CONCLUSIONS: Both tests are reliable for screening aneuploidies in the low risk population, the screen test having better performance; in the high risk population, the number of invasive procedures can be reduced by 78% with the triple test and by 84% with the screen test.