MSAFP (maternal serum alpha-fetoprotein)

The presence of AFP, a plasma protein normally produced by the fetus, in the mother's blood.

The MSAFP serves as the basis for some valuable tests.</P> AFP is manufactured principally in the fetus's liver and, also, in the fetal gastrointestinal (GI) tract and the yolk sac, a structure temporarily present during embryonic development.

The level of AFP is typically high in the fetus's blood, goes down in the baby's blood after birth, and by a year of age is virtually undetectable.</P> During pregnancy, AFP crosses the placenta from the fetal circulation and appears in the mother's blood.

The level of AFP in the mother's blood (the maternal serum AFP) provides a screening test for a number of disorders including: > >Open neural tube defects (anencephaly and spina bifida); and >Down syndrome (and other chromosome abnormalities).</LI></UL> The maternal serum AFP (MSAFP) tends to be:</P> > >High with open neural tube defects such as anencephaly and spina bifida (meningomyelocele); and >Low with Down syndrome (trisomy 21, an extra chromosome number 21).</LI></UL>