These results indicate that rapid quantification of AFP, uE3, and hCG using cost effective and highly sensitive ODI CLEIAs in the presence of Triton X-100 can be applied as an accurate, precise, and reproducible method to diagnose genetic disorders (e.g., trisomy 18 and trisomy 21) in fetuses.
Forty-eight women screened positive for trisomy 18 by second-trimester biochemical screening with human chorionic gonadotrophin (hCG) and alpha fetoprotein (AFP).
In the first step, a 0.5 MoM cut-off for AFP or for free beta-hCG resulted in detection of 37/45 trisomy 18 cases (82%) with a 10% false-positive rate.
The association of increased levels of AFP in cases of trisomy 18 with ventral wall defects and the slight increase in AFP in cases of sex chromosomal anomalies other than Turner's syndrome was found.
In this study we examined alpha-fetoprotein (AFP) mRNA expression in fetal liver at 12-15 weeks of gestation in trisomy 21 (n = 13), trisomy 18 (n = 5) and control fetuses (n = 24).
We have demonstrated that with AFP, uE3, and hCG, a separate protocol will identify a significant portion of trisomy 18 fetuses with a minimal increase in the number of amniocenteses performed.
Our protocols diagnosed trisomy 21 in a 23-week fetus with low maternal serum AFP and a trisomy 18 in a direct chorionic villus sample 2 working days after the samples were obtained.
Fetal weight does not seem to account for the lower maternal serum alpha-fetoprotein levels seen in fetuses with Down syndrome but may partially account for the lower levels seen in fetuses with trisomy 18.