Re-evaluating Down syndrome tests.
D000649:Amniocentesis; D006063:Chorionic Gonadotropin / Q000097:blood; D004314:Down Syndrome / Q000175:diagnosis*; D006801:Humans; D008423:Maternal Age; D011296:Prenatal Diagnosis / Q000379:methods*
D006063:Chorionic Gonadotropin; C024889:glycosylated HCG