Triple marker's for Down's syndrome (Second Trimester Screen)
· Quantitative determinations:
· AFP : Alpha-fetoprotein
· bHCG : Human Chorionic Gonadotrophin
· E3 : Estriol
· The efficacy of these markers in evaluating the risk of trisomy 21 is proven in the second trimester. The test can be offered to women of all ages as long as the limits as well as the advantages, of the test are fully explained.
· The result of the test represents a statistical estimation of the risk of Trisomy 21 and is not diagnostic.
· The procedure involves two stages: first blood testing and then, If called for, fetal karyotyping using amniotic fluid.
· The test is interpretable between 15 and 22 weeks after the last period.