Patent ID: 7897362

Claim:
A method for determining whether a pregnant woman has an increased risk of carrying a Down's syndrome fetus comprising: (i) contacting a biological sample from the woman in a combination assay with at least two capture antibodies, one that specifically binds an epitope of invasive trophoblast antigen and another that specifically binds an epitope of human chorionic gonadotropin, and a single detection antibody that binds an epitope of the invasive trophoblast antigen and human chorionic gonadotropin different from the epitopes bound by the capture antibodies, the detection antibody being coupled to a label that is effective to produce a detectable signal, in one assay; and (ii) detecting a signal produced by the label; and (iii) comparing the total invasive trophoblast antigen and human chorionic gonadotropin signal generated in the sample to the signal generated from a population of pregnant women carrying normal fetuses, wherein an elevated signal in the sample relative to the signal from the population of women carrying normal fetuses indicates an increased risk of carrying a Down's syndrome fetus.