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:Normal range
Comment: AFP in amniotic fluid is derived from two sources, the fetal liver and the fetal yolk sac. These two forms show varying affinity for concanavalin – A. As gestation advances, the yolk sac contribution to amniotic fluid decreases. The decreased in AFP in amniotic fluid surrounding fetuses with trisomy 21 involves proportionately equal reduction in the yolk sac subfraction and total AFP. No advantage in diagnostic efficiency has been found, therefore, in differential determination of the yolk sac subfractions. It is detectable in amniotic fluid and maternal blood at 10-12 weeks gestation (Sample: Amniotic fluid (sterile |
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