A material which is used to verify the performance of an assay intended to be used for the quantitative measurement of multiple hormone levels in a clinical specimen, in order to predict the risk of trisomy 21 (Down syndrome) as part of a first or second trimester screening assessment. Hormones assayed may include alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG), pregnancy associated plasma protein A (PAPP-A), estriol and/or inhibin A.