A novel method for the detection of down syndrome with the use of four serum markers

ective: The purpose of this study was to evaluate the use of the Lens culinaris agglutinin-reactive α-fetoprotein ratio for the detection of fetal Down syndrome in combination with traditional serum markers. Study Design: We obtained maternal serum from 530 women with unaffected pregnancies and 31 women who were pregnant with a fetus with Down syndrome at 14 to 20 weeks of gestation. Various combinations of Lens culinaris agglutinin-reactive α-fetoprotein ratio, α-fetoprotein, human chorionic gonadotropin, and unconjugated estriol were evaluated by score, without regard for the maternal age-related fetal Down syndrome risk. Results: The best combination of serum markers, according to our scoring method, was a combination of all 4 markers. This combination showed a sensitivity of 83.9%, with a 5.1% false-positive rate for Down syndrome. Moreover, in older women, high sensitivity was obtained without increasing the false-positive rate. Conclusion: The screen using all 4 markers showed high sensitivity in all age groups without increasing the false-positive rate. (Am J Obstet Gynecol 2002;187:197-201.)