Prenatal screening for Down syndrome using maternal serum markers achieves
detection rates of 60-80% with a 5% false positive rate. Improvement in the
accuracy of screening, as well as its ease and safety, will increase the u
se of such tests. The most effective of the current serum markers is human
chorionic gonadotropin (hCG), Studies on beta core fragment (beta CF), the
major urinary metabolite of hCG, have indicated that screening with beta CF
and other markers measured in maternal urine might improve the detection o
f Down syndrome and provide a less expensive and simpler test. However, rec
ent results have been unusually variable, Although it has great potential,
the true clinical value of maternal urine screening to detect Down syndrome
still remains to be determined.