The test involves measuring the amount of one or all three substances signifying pregnancy, such as alpha fetoprotein
, in blood taken from a pregnant woman to determine the risk of giving birth to a fetus with Down's syndrome and other congenital birth defects.
Down's syndrome screening in multiple pregnancies using alpha fetoprotein
and free beta hCG.
The three cancer markers are Id1, HMGA2 and Alpha Fetoprotein
These include human neutrophil elastase, human myeloperoxidase isoform c, alpha fetoprotein
, beta 2 microglobulin, and amylase.
Alternatively, a patient can opt for integrated screening, in which NT and PAPP-A are measured at 10-14 weeks, followed by the quad screen (serum alpha fetoprotein
, hCG, unconjugated estriol, and inhibin A) at 15-16 weeks, and the results are given all at once as a single risk value; if the results are positive, amniocentesis is then offered to the patient.
Types of screening covered include maternal serum alpha fetoprotein
(AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3), acetylcholinesterase (AchE), dimeric inhibin A (DIA), and pregnancy-associated plasma protein A (PAPP-A).