EARLY DETECTION OF THE 21st CHOMOSOME TRISOMY BY AFP, β-HCG AND uE3

Abstract

Trisomy 21 is the most common autosomal chromosome anomaly. Its incidence ranges from 0.3
to 3.4 per 1000 births in different parts of the world. In Egypt, the incidence of Down syndrome has
been reported to be one per 1000 births. Screening for Down syndrome through different
biochemical markers is still and will be a better basic tool for detection of Down syndrome instead
of invasive procedures. The aim of the presented study was to evaluate the triple screening test
(using AFP, β-HCG and uE3) in prenatal diagnosis of Down syndrome through comparing the
results of the test with the outcome of pregnancy. We compared these results with the results of the
double test (using AFP and β-HCG) and MSAFP test to evaluate the value of combining β-HCG,
alpha-fetoprotein (AFP) and unconjugated estriol with maternal age in this three-analyte maternal
serum screening program for Down syndrome. Triple screening test using AFP, HCG and uE3
proved to have the upper hand over MSAFP and double test in detection of Down syndrome as it has
the highest detection rate and lowest false positive rate.